For example, if you take a photo at a conference with a 12-megapixel camera, the resulting image may measure just over 3MB, preventing you from sharing it with customers that follow you on Twitter.

Crop your picture first to make sure its most important parts are prominently visible. For example, you may have a group photo that would be perfect if you could excise everyone else.

To make a GIF on your iPhone, you can convert a Live Photo in the Photos app or use apps like GIPHY. Converting Live Photos lets you make quick pseudo-GIFs with photos you've taken yourself.