Digital Image Editing: Photoshop

Factual Questions
1
      • I have Paint Shop Pro 7.whatever, and I have just found out that it cannot process images if the PSP exe and the image are larger than your physical RAM -that is, PSP does not use the swap file at all. Does Photoshop have this limitation? - MC
2

No. Photoshop can edit images only limited by disk space. In practical terms, you can edit an image almost any size. I’ve seen people edit 1Gb image files on a 256Mb RAM Mac, using Photoshop.

3

Yep, I agree. No, it’s not limited in that way.

Photoshop allocates a percentage of free memory automatically (on installation) but you can increase the settings under Edit > Preferences > Memory and Images Cache. This results in Photoshop utilising virtual hard disk space for the extra RAM. As the recommended minimum to run Photoshop (version 6, anyways) is 128, you can see that lots and lots of memory is pretty much essential.

Also, Photoshop lets you choose (if you have 2 hard drives) the order in which it’s going to add the additional memory (under the scratch disk settings in ‘Preferences’).

Obviously, this isn’t the place for a debate on the relative merits of these apps but PSP and Photoshop are very different animals.