This one is covered in the predictable place:

Draw your animation frames, either directly into the animation editor in jEmplode, or by using a third-party painting program such as Paint Shop Pro. If you are using a third-party program, make sure it can save individual images as .PNG files or save entire animations as animated .GIF files.
Or better yet, click on HELP in the Jemplode animation editor and it sends you to a page with this text:

Under the File menu, you'll notice you can Save as PNG... and Open Image... This allows you to export a single frame from your Frame Pool to a PNG file and to load a single frame back in from a GIF, JPEG, or PNG.
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Tony Fabris