We have over 20,000 product images. Initially, we loaded 640x480px images into the images directory and let zc do the work adjusting. All page load speeds EXCEPT the product detail page were acceptable. But product detail pages would sometimes reach 1 minute or time out.

We built medium (250px) and large (400px) images and loaded them into the large and medium directories... page load speeds remained the same. We replaced the 640px images with 400 px images... still very slow product detail page loads... 30+ sec.

We deleted all the images from the main images directory, kept the large and medium images in their folders. Now page loads speeds for product pages are reasonable. But, of course, there are no thumbnails for the products.

Do I need to make small images and load them into the -images- directory? Will I still have problems due to the number of images? Should I split the images into categories to reduce the single folder size?

We have two other smaller stores which run satisfactorily with about 1000 products each.