Help needed looking for new iMac

I fully agree with the advice given. The question is where to start? I've ordered on line and I like the process, as well as using their trade in process. You probably will want a computer with the same sized screen. Two things I am sure that rkaufmann would agree with me on is to buy enough RAM for all of your needs. And only get a Mac with a solid state (SSD) drive, as large as you can afford. Additionally, if you do not have a back up drive, be sure to get one as well. Now days, external drives are very reasonably priced. Enjoy your Mac.

Some general iMac purchasing considerations:

• Do a build-to-order and deal with the wait. Things are a little crazy before the holidays and even worse for 2020 with COVID. Don't wait until you are in panic mode with a dead computer on your workstation! I did that--not fun.
• Get the biggest factory SSD you can afford. Rotational drives are glacially slow, and Fusion drives are not that fast and seem to be more troublesome based on many reports here. Apple's SSDs will blow your hair back! Factory SSD pricing has come down. I paid $3000 for a 2017 5K with a 1TB SSD and i7 processor. The 2020 equivalent is $2500 and has more VRAM; all the difference is due to reductions in SSD pricing.
• Get the 27-inch with the base 8GB RAM and buy more RAM from Crucial or OWC. I saved US$100 doing that to double RAM to 16GB, which I applied to a bigger factory SSD.
• Remember that RAM in the 21.5-inch models is NOT user upgradeable after they are built. Apple won't upgrade one and many Apple Authorized Service Providers will not either. It is that hard.

Pro apps need power and, as you said, image processing is getting more complex. Considerations based on your use:

• Go for the i7 or i9 processor

Allan is correct, in your case the CPU (i7 or greater) and GPU do not matter. There are no Apple Black Friday deals on iMacs (at least there never has been) but you can wait to see.

• Buy the largest SSD you can possibly afford.
• Buy it with 8GB of RAM and then purchase 32GB or 64GB of RAM from www.macsales.com or Crucial.com, installing is a 5 minute process and requires no tools, in short almost anyone can do a RAM upgrade.
• If you decided to buy a 21.5" model buy it with 32 GB of RAM and the largest SSD you can afford.

So you have basicsally heard the same thing from 2 experienced users, if you buy these from Apple's online store I think you will be very pleased. I recently got a 2020 27" iMacs (actually we bought 2) and are extremely happy with both. The config I got was the i9 CPU, basic GPU, 2 TB SSD and then bought 32GB of RAM from www.macsales.com. I also do some photography but I'm not a pro, I also avoid Adobe apps as their licensing model is ridiculous, their support is awful and I have seen many on these forums have Adobe issues. So I search for alternatives and have been lucky, my photography needs are not demanding and for me I have found the Apple Photos app to be adequate for my needs. However, you may be a creative professional and need apps that have much more power that what I need. So again, assess your needs.

You are taking the wrong approach to buying a new Mac, what you should state is how you use a computer and what size iMac you are after. Then we can begin matching a computer that more suits your needs. NEVER buy a computer based on how much it costs, when you do that you can underbuy and become frustrated because they computer your bought was never designed to do the work you do.

That would be like buying a mini cooper and then being frustrated because it doesn't haul 8000 lbs. If you knew you were going to haul 8000 lbs, then buy a suitable vehicle.

Also, you can buy from Apple's online store, that is how I (and millions of others) buy their iMacs.

Yes I agree on these points. Just tell us how you intend to use the computer and the apps or types of apps you use then we have a starting point.