How To Determine Visual/Digital Quality & Other Key Basics That Are Related

Question

so there were really good answers on http://forums.adobe.com/thread/1216617
premises
the first thing is "Every Time you resample an image interpolating it up or down in pixel size you loose some image quality [as] all pixels have been generated by computer algorithms" -- http://forums.adobe.com/message/5340231#5340231
this is understable because of "When downsizing, neighboring pixels will be beldned ito one and their colros mixed, when upsizing the program has to make up pixels to fill the gaps" -- http://forums.adobe.com/message/5338138#5338138
though much of the resizing won't cause any significant (meaning noticeable) lose of quality on the screen (and i guess in print) unless you enlarge the photo alot
question: so if you don't know what is the visual quality of a photo, and say you are like most ppl, who dont have a photographer's eye, what are other effective ways to determine this? is there a program that can output a number which indicates the photo's visual quality?
question: to pick a size where visual quality is still good, there are general rules like the one for printing -- http://forums.adobe.com/message/5340231#5340231 -- how about digitally? on the computer screen? this is about picking the right size
a related question: when you enlarge a photo, the data (bytes) increases which means that data does not correspond with visual quality because enlarging actually decrease the visual/digital quality. so if we can't use data to get a feel for the visual quality, what can we do? (actually that's basically getting to the same question as the first one, just asked from a different approach)
solved-question: most of the comments in the answers linked above talked about increasing visual quality which had nothing to do with the goal or the question asked. so the question on increasing visual quality is solved, with the answer being "there are currently ways, none of which are really promising"
question: is it really true that none of adobe's products can easiely do the simple and common and important problem of ** batch resize ** ? -- http://forums.adobe.com/message/5341155
honestly all these questions are very basic, and im sure by 2013 there's at least one good guide covering all these basic basic stuff -- just link to your wonderful & ** concise ** guide on your blog, this forum from years ago, or wherever
I VALUE YOUR TIME AND SO SHOULD YOU -- GOOD GUIDES ARE THE BEST

Answer 1

It's too late and I'm too tired to hit everything in your message above, but I do want to answer this one:
excessphotos wrote:
question: is it really true that none of adobe's products can easiely do the simple and common and important problem of ** batch resize ** ? --
In Photoshop, check out File - Scripts - Image Processor.  I think it may answer your needs.
But if Image Processor doesn't quite get you there, Dr. Russell Brown (with Adobe) has published an Image Processor Pro script that's amazing in its capability.  You can find that (for free) here:
http://www.russellbrown.com/scripts.html
-Noel