I had 12800 images in my library. After Constant Contact update the library took forever to open - even on my 1gbit fibre connection. Obviously developers hadn't tested update with a full library of images.
It took 5 minutes to change one image and hence couldn't complete the newsletter I was working on.
Therefore tried to remove all the old images from the library in an attempt to speed up the process that CC broke, but guess what - the developers don't allow you to sort them in date order (i.e you can't sort by oldest first) so another huge headache!
Some poor design decisions from the developers I'm afraid that causes a huge problem for some of the users.