BatVink - I had the same issue regarding the
impalasolutions.net site... The owner can upload images with every new 'Product' they add.
However, there's no limitation on these images (other than a helpfull warning saying: Don't exceed 640x480, and use jpegs).
So, I came across this nifty little PHP library called phpThumb.
Bloody awesome little bit of software - it uses the GDI library to generate thumbnails, and even the full-sized image to specified file sizes, resolutions, file types, apply effects, overlay text, etc, etc.
Then, each image is cached so there's no extra strain on the server later (if caching's turned on of course).
You'll notice the settings from the image URLs on the site - I limit all the thumbnails to 50x50px, with a max filesize of 8192bytes.
http://www.impalasolutions.net/php_includes/phpthumb/phpThumb.php?src=../../images/products/Mitsubishi_HDTVl_13DV42P2HD.jpg&w=50&h=50&f=png&maxb=8192
So, it's upload once - process once (first view) - view many many times
I suggest you have a look-see, as it really does mean you are basically holding the uploader's hand as to what they do, whilst keeping lightning fast pages
phpThumb