Excel, 4500 pictures and sort....

ok,

So I built a nice little macro in my excell sheet that when triggered takes a column of absolute addresses to 4500 pictures and makes thumbs, avoiding all that mess with storage in the sheet and such. This same sheet has values associated with each photo in columns next to them... Where the photo was taken, who took it, what it is, what date etc, and a few empty spots of data that all the photo takers want to sort and fill....

These other columns sort real nicly by catagories when the sheet has no pictures on it, via row 4. The catagories snap, carrying each rows catagories with them quickly...

Put the photos on the sheet and do a sort and it whigs out, freezes and crashes when it starts sorting. I can see the pictures scrolling by as it tries to go from 1253 to the next selected row at 2314 for example. and it seems to go on and on and on, sometimes crashing the sheet... The macro generates pictures faster than the sort can move them in most cases.
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Now Ive thought to erase the photos before each sort, then re-generate them; but Im not sure if the folks Im working with can keep that in mind too.

I dont want the sheet to whig out and loose all the changes made to those empty spots if the workbook fails and crashes when someone is working with it...

SO-
my question is. How can I stop this action by clearing before a sort when the sort is already triggered.....

OR, perhaps better yet, how do I see just the cells that are visable, so a macro can be clicked to only draw those. For example, rows 2400 through 2450 are on the screen, but there are 4500 rows... what command will tell me what rows are actually visable, such that I can insert just those pictures into only those rows?

Thanks for any insights you may have....