I would like a simple and quick way to save a copy of an image in Photoshop, with an auto-incrementing filename. Ideally, a single button to capture a frame in a stop motion animation. In other words, I would like to save a copy of the working image as a JPEG without any interactive prompts and the filename will automatically increment a count.

For example, if I’m working with a file “test.psd”, I want a single action that will save a copy “test_0001.jpg”, and subsequent calls will save “test_0002.jpg”, “test_0003.jpg”, and so on.

By default, Photoshop will overwrite existing files, and it would be quite tedious to manually “Save As” for hundreds or thousands of images. Fortunately, Photoshop offers a scripting interface to call user defined scripts. Custom scripts can even be loaded into Photoshop and executed as an Action.

The following snippet can be saved as [Photoshop Directory]/Presets/Scripts/saveFrame.jsx, and after restarting Photoshop you should see “saveFrame” under File -> Scripts.

main();

/***
 * Scripted "save as" with incrementing filename
 *   e.g., test_0001.jpg, test_0002.jpg, ...
 *
 ***/
function main() { 
	if (!documents.length)
		return;
	cnt = 1;
    try {
        var Name = decodeURI(activeDocument.name).replace(/\.[^\.]+$/, '');
        var Path = decodeURI(activeDocument.path);
        var saveFrame = Path + "/" + Name + "_" + zeroPad(cnt,4) + ".jpg";
        //
        // find the next available filename
        while ( File(saveFrame).exists ) {
            cnt++;
            saveFrame = Path + "/" + Name + "_" + zeroPad(cnt,4) + ".jpg";
        }
        //
        // save as, change the default JPEG quality here as needed
        SaveJPEG(File(saveFrame), 9);
	} catch(e) {
        alert(e + "\r@ Line " + e.line);
     }
}

function SaveJPEG(saveFile, jpegQuality) {
	var doc = activeDocument;
	if (doc.bitsPerChannel != BitsPerChannelType.EIGHT) 
		doc.bitsPerChannel = BitsPerChannelType.EIGHT;
	jpgSaveOptions = new JPEGSaveOptions();
	jpgSaveOptions.embedColorProfile = true;
	jpgSaveOptions.formatOptions = FormatOptions.STANDARDBASELINE;
	jpgSaveOptions.matte = MatteType.NONE;
	jpgSaveOptions.quality = jpegQuality; 
	activeDocument.saveAs(saveFile, jpgSaveOptions, true, Extension.LOWERCASE);
}  

function zeroPad(n, s) { 
	n = n.toString(); 
	while (n.length < s) 
		n = '0' + n; 
	return n; 
};

Using Photoshop scripts you can automate any task and even create animation effects. In CS6 you can render a series of images as a video, alternatively, you can create the image frames in Photoshop and use ffmpeg to render the video.

If you want to use ffmpeg to render a series of images, you could use the following command,

$ ffmpeg -r 30 -f image2 -i test_%04d.jpg -vb 1M -r 30 test.webm

Here is a simple (90 frame loop) example animating a series of scripted lighting effects,

The above video is embedded in this page using the following html,

<video id="test_test" poster="test_0001.jpg" preload="auto" loop autoplay>
    <source src="test.mp4" type="video/mp4" />
    <source src="test.webm" type="video/webm" />
    <source src="test.ogv" type="video/ogg" />
    <object width="600" height="360" type="application/x-shockwave-flash" data="test.swf">
        <param name="movie" value="test.swf" />
        <img src="test_0001.jpg" width="600" height="360" alt="test" title="No video playback" />
    </object>
</video>