Creating Animated GIF Files for Electronic Presentations Using Photoshop

Transcription

1 Creating nimated Electronic Presentations Computers Computers in Radiology Chun-Shan Yam 1 Jonathan Kruskal Michael Larson Yam C-S, Kruskal J, Larson M Keywords: movie clips, Photoshop, PowerPoint DOI: /JR Received September 19, 2006; accepted after revision November 21, ll authors: Department of Radiology, Harvard Medical School, Beth Israel Deaconess Medical Center, WCC, Room 306, 330 Brookline ve., Boston, M ddress correspondence to C.-S. Yam (csyam@bidmc.harvard.edu). WEB This is a Web exclusive article. JR 2007; 188:W485 W X/07/1885 W485 merican Roentgen Ray Society Creating nimated GIF Files for Electronic Presentations Using Photoshop OBJECTIVE. Our objective is to present a simple method for converting movie clips to animated GIFs (graphics interchange format) using Photoshop. CONCLUSION. lthough animated GIF is a more reliable format than movie clips (e.g., VI and QuickTime) for presenting dynamic data sets in PowerPoint presentations, this output format is not available on most radiology workstations. Therefore, many academic radiologists still experience the problem of incompatible codecs and missing file links when trying to show movie clips in their PowerPoint presentations. One way to resolve this issue is to convert the movie clips to animated GIFs. In this article, we provide a simple method for this conversion using Photoshop a common software application used by radiologists. nimated GIF (graphics interchange format) and movie clips (e.g., VI [Microsoft], QuickTime [pple Computers], and MPEG [Motion Picture Experts Group) are the two most popular file formats used by radiologists for presenting dynamic data sets (movie loops of images) in Microsoft PowerPoint. lthough the basic purpose is the same that is, displaying data set images as a movie loop, these two types of file formats are rather different in file structure and PowerPoint compatibility. First, movie clips are usually created using special software algorithms called codecs (COmpressor and DECompressor); an animated GIF does not require a codec. Second, movie clips must be linked externally to PowerPoint, but an animated GIF is embedded as part of the presentation file, similar to other images such as JPEG and BMP. Given these two merits, animated GIF is a more appropriate choice. Unfortunately, many academic radiologists still struggle with the issue of incompatible codecs and missing file links when showing movie clips in PowerPoint [1]. survey in our department (94 radiology users: 52 faculty, 32 residents, and 10 fellows) yielded the following interesting results. Most users report that animated GIF is not available on their workstations, only movie clips. Some realize the advantage of using animated GIFs over movie clips but do not know how to convert the files. nd surprisingly, no one realized that dobe Photoshop is one solution, even though all these users already have the software installed on their computers (i.e., departmental site license). In this article, step-by-step instructions for converting common movie clips (e.g., VI, QuickTime, and MPEG) to animated GIFs and creating animated GIFs from image sequences using Photoshop will be provided. Software Requirements dobe Photoshop is now a common desktop application used by academic radiologists to prepare digital images for electronic presentations and online publications. Basic techniques for using Photoshop have been documented previously [2 4]. The latest version of this software is 9.0 or Photoshop CS2 [5]. The functions discussed in this article for converting and creating animated GIFs are also available in other versions of Photoshop; therefore, users do not necessarily need to purchase the latest version. However, for users who do not have Photoshop, a 30-day free trial of Photoshop CS2 can be downloaded from the dobe Website [5]. Installation of Photoshop is straightforward for both Macintosh (pple Computers) and PC users. lthough Photoshop CS2 and Microsoft Windows XP Professional are used in this article, the general instructions provided can be applied to other versions and platforms (e.g., Photoshop in Macintosh OS 9.2, 8.0 in Macintosh OS ; and 9.0 in both Macintosh OS and Windows 2000). Besides JR:188, May 2007 W485

2 Fig. 1 Launch of dobe ImageReady (dobe product screen shots reprinted with permission from dobe Systems Incorporated)., Screen capture of dobe Photoshop CS2 shows two options for launching ImageReady from Photoshop. B, Screen capture of ImageReady CS2 shows addition palette, nimation. Photoshop, QuickTime Player (pple Computers) is also required. The latest version is 7.0 for both Macintosh and PC, and it is available as freeware from the pple Website [6]. It is important to note that although both Photoshop and QuickTime are needed for creating animated GIFs, neither of these applications is required for subsequent PowerPoint presentations that is, they don t need to be installed on the client computers. ccessing nimated GIF Functions In addition to its comprehensive digital image processing tools for manipulating images, Photoshop also provides easy-to-use functions for creating animated GIFs. However, these functions can only be accessed via dobe ImageReady, a sister application bundled with Photoshop. lthough ImageReady is designed for and capable of creating various types of Web applications, we will discuss the functions for creating animated GIFs only. Launching ImageReady In Photoshop, select File Edit in Image- Ready from the top menu (or click on the last icon at the Tools palette) to activate Image- Ready (Fig. 1). lternatively, ImageReady can be launched directly from the desktop (i.e., Start Programs dobe Image- Ready CS2). The screen layout of Image- Ready is similar to Photoshop but with an additional palette: nimation (Fig. 1B). This additional palette is for creating animated GIFs. If this palette is not displayed, select Window Show nimation from the top menu to make it visible. This is the only palette needed for this tutorial. Closing the remaining palettes (e.g., Options, Info, Color, and Layers) will maximize the work space (recommended). Tutorial # 1: Converting Movie Clips to nimated GIFs Step 1: Extracting images from movie clips In ImageReady, select File Open from the top menu to select a movie clip file. For this tutorial, a sample movie clip, xial.mov (QuickTime format, CinePak codec, 15 frames per second [fps], RGB color, 6.02 seconds, and 5.91 MB) is used (Fig. 2). This video clip can be viewed at Figure S2. Other movie clip formats such as VI and MPEG can also be used for this tutorial. ImageReady should recognize the movie clip file extensions.avi,.mov,.qt and.mpg. If any of these extensions do not appear in the file selection dialog box as shown in Figure 2, install QuickTime Player first (see Software Requirement). fter selecting the file xial.mov, click on the Open button to continue. In the Open Movie window (Fig. 2B), the first image of the movie clip is displayed. In this window, users are required to select an option for loading the movie: the entire movie clip or a part of the movie clip. The default setting is for entire movie (i.e., From Beginning to End). However to load only a portion of the movie, use the slider at the bottom right to specify a range of images on the time line (see Fig. 2B). ImageReady also provides the option for frame-skipping (i.e., loading every other frame, two frames, etc.). The main purpose of using these optional loading settings is to reduce the file size when the output animated GIF is oversized. In our experience, the typical file size of an animated GIF with 200 images ( pixels) is about 10 MB. So, if the file is already a reasonable size, such as several MB, these two optional settings are not needed. For this tutorial, the default option is selected: From Beginning to End (Fig. 2B). Click on the OK button to load the movie clip file. Subsequently, the images are extracted from the movie clip and placed into the nimation palette as individual frames (Fig. 2C). These frames are automatically placed in the same order as in the original movie clip. In this B W486 JR:188, May 2007

3 Creating nimated Electronic Presentations B C D Fig. 2 Process for converting movie clips to animated GIFs in dobe ImageReady CS2. (dobe product screen shots reprinted with permission from dobe Systems Incorporated.), Screen capture of Open dialog window. B, Screen capture of Open Movie window shows optional movie loading settings. C, Screen capture shows playback and scroll buttons at bottom of nimation palette. D, Screen capture shows actions for adjusting time delay values in nimation palette. (Fig. 2 continues on next page) sample case, a total of 91 frames are created (15 fps 6.02 = 91 seconds). Users can now preview the animated GIF by using the playback buttons or the scroll button at the bottom of the nimation palette (Fig. 2C). There is a time de- JR:188, May 2007 lay value at the bottom of each thumbnail frame. In an animated GIF, time delay is used for achieving the animation effect during playback; it is analogous to the fps parameter in movie clips. By default, ImageReady calculates the delay time value using the fps parameter of the movie file to maintain the same playback speed for the animated GIF. With 15 fps for the original movie clip, the time delay is set to 0.06 second (or 1 / 15 = 0.06). W487

4 Fig. 2 (continued) Process for converting movie clips to animated GIFs in dobe ImageReady CS2. (dobe product screen shots reprinted with permission from dobe Systems Incorporated.) E, Screen capture of Save Optimized s window shows typical parameters for exporting animated GIF image. Step 2: djusting playback speed and image processing (optional) s an option, users can adjust the playback speed for the animated GIF by changing the time delay values. For example, users can adjust the playback speed from 15 fps to 10 fps using the following two steps. First, select all image frames from the nimation palette (i.e., click on the first frame and scroll to the last frame then click on it while holding down the Shift key). Now, all the image frames should be highlighted. Next, click on the time delay value (i.e., 0.06 second) from any one of the selected frames and then select 0.1 second from the dropdown list (Fig. 2D). However, in our experience, playback speeds for most movie clips obtained from radiology workstations are suitable for PowerPoint presentations. Unless there is a need to present the data sets in slow motion, this option is not necessary. In addition to adjusting playback speed, users can also apply image processing functions for adjusting the brightness and flipping, rotating, cropping, and resizing of the images globally. However, PowerPoint also provides similar functions in the Picture Toolbar. In our experience, using the functions provided by PowerPoint is more straightforward. Image cropping is not available for animated GIFs in PowerPoint. For example, to remove patient information from the image frames, users must use the crop function in ImageReady. Step 3: Exporting the animated GIF In ImageReady, select File Save Optimized s from the top menu. In the Save Optimized s window, select Images Only (*.GIF) for the Save as type parameter and Default Settings for Settings (see Fig. 2E), and then navigate to the destination folder for exporting the animated GIF. For this sample case, the animated GIF file is saved to the same desktop folder as the original movie clip with a filename xial.gif (6.11 MB). This file can be downloaded from Figure S2E. Tutorial # 2: Creating an nimated GIF from a Sequence of Images The essential steps for creating an animated GIF from a sequence of images are similar to the previous tutorial except for Step 1, in which the image frames are imported directly from a folder rather than extracted from a movie clip. For demonstration, a desktop folder JPEG containing a sequence of 20 JPEG images ( pixels) has been prepared. Other common image formats such as TIFF, BMP, and PNG can also be used for this tutorial. zipped file of this sample image sequence JPEG.zip (615 KB) is available as Figure S3 for download. Step 1: Importing a sequence of images In ImageReady, select File Import Folder as Frames from the top menu to select the folder (Fig. 3). In the Browse for Folder window, select the folder containing the image sequence. For this sample case, the sample folder JPEG located at the desktop with the 20 sample JPEG images is selected (Fig. 3B). The images are named sequentially as CT01.jpg, CT02.jpg, CT03.jpg, and so on E to CT20.jpg. Next, click on the OK button to load the images. Images will be loaded in the order according to their file names (Fig. 3C). Multiple image sequences can be loaded into the same animated GIF. ImageReady will load all the images within the selected folder according to the alpha numeric order of their file names. Step 2: ssigning time delay values Unlike the previous tutorial in which the time delay value is extracted automatically from the movie clip; users need to specify this value for the playback speed. Depending on the number of images and the user s presentation preferences, a playback speed between 10 and 15 fps is appropriate for most dynamic data sets. For this sample case, 0.1 second (or 10 fps) is used for the time delay value (Fig. 3D). The instructions for setting the time delay value are provided in step 2 of the previous tutorial. Similarly, users can apply image processing functions to the images globally as described in the previous tutorial before creating the animated GIF. However, for this sample case, we do not use these functions. Step 3: Exporting an animated GIF The instructions for exporting an animated GIF are identical to the previous tutorial. Select File Save Optimized s from the top menu and then save the file. For this sample case, the animated GIF is saved with a filename CT.GIF (2.51 MB). Using nimated GIFs in PowerPoint lthough animated GIFs contain multiple images, technically, they are still classified as images. Therefore, using animated GIFs in PowerPoint is similar to other common images such as JPEG, TIFF, and BMP. Users can insert animated GIFs into PowerPoint by selecting the Insert Picture From File function from the top menu. lternatively, animated GIFs can be inserted using drag and drop. They can then be resized and rotated using simple mouse clicks (Fig. 4). In addition, users can apply image processing functions available in the Picture Toolbar (e.g., Contrast, Brightness, and Rotate Left) and putting annotations (e.g., drawing arrows, circles, and text) on top of the animated GIFs (Fig. 4). If the Picture Toolbar is not displayed, select View Toolbars Picture from the top menu to make it visible. The usage of these functions is straightforward and has been discussed in previous articles [7 9]. s discussed previously, the crop function is disabled for animated GIFs in Power- Point and is only available in ImageReady. The instructions for cropping patient information W488 JR:188, May 2007

5 Creating nimated Electronic Presentations B C D Fig. 3 Process for creating animated GIF from sequence of images in dobe ImageReady CS2. (dobe product screen shots reprinted with permission from dobe Systems Incorporated.), Screen capture shows function for loading image sequences. B, Screen capture shows Browse for Folder window. C, Screen capture shows sequence of images loaded into nimation palette. By default, time delay value is not set (i.e., 0.00 seconds) and must be assigned manually after loading image sequence. D, Screen capture shows action for assigning time delay value of 0.1 second (or 10 frames per second) for image sequence. JR:188, May 2007 W489

6 Fig. 4 Screen capture of Microsoft PowerPoint 2003 shows tools and functions for manipulating sample animated GIF, xial.gif, created in tutorial #1. It also shows capability of using arrows and text for annotation. (Microsoft product screen shots reprinted with permission from Microsoft Corporation.) from animated GIFs using ImageReady are discussed in tutorial # 1. Unlike movie clips that must be manually selected for auto-play (PowerPoint will prompt for this option on movie insertion), an animated GIF plays automatically. Similarly, movie clips provide options for looping and rewinding (right click on the movie and select these functions at the pop-up window), whereas animated GIF loops and rewinds the movies automatically. FOR YOUR INFORMTION Limitations and lternatives nimated GIFs are a more appropriate alternative than movie clips for presenting dynamic data sets in PowerPoint. However, there is one known potential issue the animated GIF does not support audio. Fortunately, in our experience most movie clips used by academic radiologists do not require sound. The tutorial provided in this article can still be used to convert movie clips containing audio, but the animated GIF will not contain sound. For academic radiologists who may not have access to Photoshop, there are open-source freeware applications that can also be used for creating animated GIFs, such as GIFfun for Macintosh ( and Un- FREEz for PC ( Some of the process steps described in the tutorials can be automated using a macro (Photoshop ctions). The basic approach for creating macros in Photoshop is similar to that in PowerPoint [10]. However, this feature is beyond the scope of this current article. The data supplement accompanying this Web exclusive article can be viewed from the information box in the upper right corner of the article at: Conclusion Today, many academic radiologists still experience problems showing movie clips in their PowerPoint presentations because of incompatible codecs and missing file links. One answer to this problem is to convert the movie clips to animated GIFs most radiology workstations only produce movie clips. In this article, we provide a simple method for this conversion using Photoshop a common software application already used by radiologists. Using Photoshop, academic radiologists can now present their dynamic data sets as animated GIFs in PowerPoint without any codec or file-link issues. References 1. Yam C-S, Kruskal J, Larson M. Using movie clips in PowerPoint presentations: part 1, compatibility issues. JR 2005; 185: Stern EJ, Richardson ML. Preparation of digital images for presentation and publication. JR 2003; 180: Taylor G. Initial steps in image preparation. JR 2002; 179: Corl FM, Garland MR, Lawler LP, Fishman EK. five-step approach to digital image manipulation for the radiologist. RadioGraphics 2002; 22: dobe Photoshop Website. vailable at: www. adobe.com/products/photoshop. ccessed February 2, pple QuickTime Website. vailable at: ccessed February 2, Schreibman KL. Getting images into PowerPoint. JR 2001; 177: Lababede O. Digital image editing using Power- Point: part 1, introduction to the image-manipulation commands. JR 2004; 183: Lababede O. Digital image editing using Power- Point: part 2, practical applications of the imagemanipulation commands. JR 2004; 183: Sistrom C, Honeyman-Buck J. simple method for importing multiple image files into PowerPoint. JR 2004; 182: W490 JR:188, May 2007