Bitmap graphics: Paint.NET . Yeah, Windows, but it works quite well. IIRC, I've read that, at least at one point, it ran under Wine. KDE's Krita just hit 4.0 . I haven't used it, but there are lots of nice comments about it floating around. In the Linux world, there's also Pinta that I've used a few times. On Ubuntu 16.04, out of the default repositories, it complains about this or that missing or not being signed/blessed/something -- or did, last I used it. But it works ok, at least for the quick and dirty tasks I had at hand at that time.

Vector graphics: Inkscape

Adobe support is, in my experience, truly horrible. I once spent a cumulative 7.5 hours on support calls before I finally got a front line call center employee to go back to their supervisor, after being given the wrong answer once, and prod them into paying attention and looking further and, lo and behold, generating the correct legacy license code I -- rather, the person I was helping -- was entitled to as an owner/licensee of the full-blown Creative Suite.

Basically, I knew more than the support supervisor about this problem. I just had to find someone in support with the interest and guts to push their supervisor to actually pay attention and execute the solution.

7.5 hours. For what should have been one 10 minute support call.

After that, I vowed that as for myself, at least, Adobe would never get another dime from me.