Animated images -- otherwise known as GIFs -- have been around for 25 years, but they saw a resurgence of popularity starting in 2013. If you want to make your own, PicGIF from Pearl Mountain offers a quick, easy solution.
With PicGIF you can turn continuous snapshots into animated GIFs, create GIF photo slideshows from your pics in iPhoto (or other apps), and transfer short videos to animated GIFs. What's more, it lets you re-edit your existing GIFs.
PicGIF supports can import lots of file formats, including hundreds of image formats (JPEG, TIFF, BMP, PGN, TGA, RAW, PIC, etc.), GIFs, and just about all common video formats (MOV, MPEG, MP4, M4V, 3GP, AVI, etc. You can combine multiple formats into a single GIF.
To get started, open PicGIF and click "Add Photo" to add photos or existing GIFs. Click "Add Video" to add short videos. Alternatively, you can drag pics or videos to the Add Photo and/or Add Video windows in the PicGIF user interface. Note that there's a 300 photo limit, so don't be greedy.
Click the Size combo box on the Setting panel to choose the GIF size you want. There are a variety of preset sizes, plus an option to customize the size you need. You'll want to experiment and tweak to get the best results.
If the GIF size you set is bigger than your actual images, you can set different fill modes: fill, fit and stretch. After selecting your mode, you can choose a specific color to fill the rest of the GIF canvas where the images can’t cover.
Once you've loaded your pics and graphics, the app has customizing features that let you tweak the size, frame delay, frame order and sequence, text, and more. For example, you can increase the frame delay to make the GIF play faster or decrease it to make it play slower. You can even adjust individual frame order. Again, it will take some experimentation to get the best results.
With the text editor, you can insert text and captions, then personalize the font, style, color, outline and shadow. PicGIF offers a real-time preview of the GIF while you're editing, which is very convenient.
PicGIF also provides you with an abundance of export and share options. You can export the GIF to the Finder, send via email, or send via iMessage (in macOS 10.8 or above).
My one complaint: you can't add audio to your GIFs. That's a shame because it would truly make them more personal.
That said, PicGIF is easy to learn and fun to use. As long as you're willing to do a little tinkering, you can make some cool animated GIFs and share 'em with the world (or just family and friends, if you wish.)
PicGIF is available at the Mac App Store for $19.90. It requires macOS 10.7 or higher.