I'm not an artist, but I would recommend checking out Krita, it's really nice & it's 100% free to use.
Also I believe Procreate is really popular, but it requires an iPad. My sister uses it for designing tattoo stencils with.
Also, if you are interested in Voxel art design, then there's always magicavoxel which is also 100% free to use.
Anyway, I personally use Photoshop myself as it's what I've been using on & off for over 20 years.
As for Esmeralda putting her gamejam games online, they are exporting for html5 & uploading them to itch.io which supports html5 game uploads - you can upload & share other builds too.
Quick note: Visionaire Studio html5 builds do not currently have video support, so keep that in mind when you create your games.