Hey Ryam, what kind of tools are you using for the art assets and animating? I don't know about the new GameMaker version, but previous versions didn't have the best built-in tools for sprite work. For animating, using tools with "onion-skinning" is very useful as this lets you see a ghost of the previous frame. In the past, I've used Graphics Gale which I believe is free for most things and will allow you to export sprite sheets (but not export GIFs), but I've also heard some good things about Pyxel Edit which I haven't touched myself yet.
As J said though, using programmer art for game jams is a good idea at times. Personally I flip back and forth between programming and art. When I get stuck trying to "perfect" art assets, I go back to programming, and when I get bogged down with rewriting optimizations, I switch back to art. The most important thing for this is to keep motivation up, so work on what is most interesting to you.
The dog animation definitely looks very nice so far! A minor suggestion would be to have the tail wag back and forth rather than uncurl in the idle animation.