a fun editing resource.

https://photomosh.com/

It allows you to create static and .gif images with glitchy effects.

Free version applies a watermark, but negating that (unless they change its position in the future) it's as simple as
- adding ~50px to the bottom of your starting image (and filling it in with a color that matches if you want to apply certain effects)
- cropping it off in GIMP or other .gif editing software 🤷