RE: Picasa & Hello - Some of the best photo software available (free too)
PHOTOSHOP is pretty pricey unless you are doing an upgrade. Then again, the price of anything is relative to ones own pocketbook.
If you are on a MAC, and someone else has it, it is possible to "drag and drop" the application - totally functional.
If you are on a PC, however, it must be installed
SUGGESTION: look for an old version of PHOTOSHOP ELEMENTS I, This is 100% free of cost
check with your friends
good luck
marwen1