Desktop question

I would recommend a 27" iMac with 8 GB of memory (to be upgraded by you to 16GB for less than ½ of what Apple charges via MacSales.com or Crucial.com) and the largest SSD drive your budget can afford, 1TB would be fine and last you a long time.

Since the new Mac will have Catalina on it many of the apps which are 32 bit on your old Mac will not work with Catalina. Download and run the free app GO64 to find out which of those apps will have to be upgraded or replaced with an alternative.

I run 27" iMac with 16GB of RAM and have no problems with memory with large Photos libraries (57,000+ photos). I've edited large (350mb) images and have had no problems with that much memory.

Well about the best advice you are going to get is on the hardware:

• 21.5" iMac buy one with a minimum of 16GB of RAM (more is better!!!!) and the largest SSD you can afford. RAM is not user upgradeable on 21.5" iMac and the HD and Fusion drives are really not good.

• 27" buy one with the base 8GB of RAM and upgrade to a total of 40 GB RAM (add 2 x 16 GB DIMMS to the empty slots) using either Crucial.com or Macsales.com RAM . Also buy the largest SSD you can afford.

Sorry... what, exactly, is your question?

Are you trying to make the old machine you have more usable, or are you asking for advice on a new machine?

Do you know what apps/programs your wife uses for her photography. Apps like Adobe Lightroom and Photoshop can be very memory intensive.