When I use Windows to look at photos, can I make the 'thumbnails' bigger?

[Katymac]

Otherwise I think I am going to have to get glasses

Yes. Click on view, then filmstrip.

Thanks but I can't see the folders that way & I am sorting

Do you have Vista? If so, you can click on Views - Extra large icons.
I usually use Picasa 3 - the thumbnails are fairly big in that.

Or if you have XP then TweakUI from here does it easily.

WinXP powertoys

OK I have XP

So I download something?