I use GIMP. I also use a number of other FOSS software programs, I suppose like Photoshop users use Lightroom etc.
Gimp is not as fully featured as Photoshop, but does most of what Photoshop can do, and all I have needed. I would add Rawtherapee, Lightzone, and Darktable, all very capable and free (in both senses) programs developed by enthusiasts and experts in the Linux community (as Android and several of the past Mac OS were), two of which dovetale into Gimp reasonably well. There are those who decry free software, including all FOSS, generally those who haven't used it.

I'd also search out and add various plugins from G'Mic and others, scripts etc. which add further functionality. The range of sharpening and contrast tools there is very good.

Gimp has changed and improved over the years as all such software has, so impressions from a try 10 years ago are not that useful.

My print driver, Turboprint, also meshes with Gimp in its menus so I can print directly from the program. Sadly Qimage, which I am very impressed with trying on a Windows machine, does not run under Linux.

With every change of software there will be a learning curve. I'm used to the Gimp, so it feels natural. You won't be, so it won't feel as good until you are.

These programs won't cost you anything, so worth giving a go, but do give them a good try, not a "doesn't feel familiar, can't work out how to do something first time, therefore will give up" try. Gimp and its friends are very powerful tools, if they had a commercial reason to push them in the market they'd be far more well known and used.

Hope this of some use.

I am using Catalina and discovered that my favorite Photoshop Elements will not run. HOWEVER, i have always provided a second partition on which i run the PREVIOUS OS X system. That way if i have a problem with anything I can boot into that partition and work on a problem, or in this case if i really want to use PSE, i have Mojave there to use. Unfortunately, Mojave only runs PSE partially. Those problems i have to work out. But the point is, in my opinion, have a partition on your system that's nearly up to date, so you can run a good number of your old favorites until you find an alternative that will work for you. Yes it's a pain to have to boot into another portion when you want to use your favorite apps, but you can spend a lot of time and money trying to find something else! You don't have to use half of your space to do this either. Make a partition that is minimal for your setup, and you won't regret it! Have done this for a couple of decades. Oops!! Just dated myself!

I've been using GIMP for years. Never got into Photoshop because it was like $600 or $700 back in the film days. GIMP's a very powerful program that does what I need (and WAY more!) There are a number of free and low-cost options; my advice would be to just pick one and get good at it. Here are some possibilities:

GIMP
Darktable
NX Studio (if you're a Nikon user; if not, each camera maker has its own program)
Picture Window Pro
Raw Therapee
Photoscape X

Plenty to work with!

Recently I made a HUGE error: I got an email message to update my operating system on my Mac to Big Sur. I installed it. Little did I know that I was making my CS6 Photoshop program and others non-functioning. Adobe of course wants everyone to pay a monthly subscription fee to have Photoshop and I am now looking into other options. So far the one I am gravitating to is Gimp. It is similar to Photoshop but no fee. I'm wondering if any of you UHH members have switched over to Gimp and if you have, how do you like it? I've been using Photoshop my whole photographic time and didn't want to have to learn a whole new program. I have downloaded Affinity Photo for the free 90 day trial period but it's not really very user friendly. Thanks for your advice in advance.

Recently I made a HUGE error: I got an email message to update my operating system on my Mac to Big Sur. I installed it. Little did I know that I was making my CS6 Photoshop program and others non-functioning. Adobe of course wants everyone to pay a monthly subscription fee to have Photoshop and I am now looking into other options. So far the one I am gravitating to is Gimp. It is similar to Photoshop but no fee. I'm wondering if any of you UHH members have switched over to Gimp and if you have, how do you like it? I've been using Photoshop my whole photographic time and didn't want to have to learn a whole new program. I have downloaded Affinity Photo for the free 90 day trial period but it's not really very user friendly. Thanks for your advice in advance.