@enchantress6274 Honestly, if you're using thesims3.com to store your in-game screenshots and memories, you could do a lot better. The site is barely being maintained these days and may eventually contract or disappear altogether, or at least lose some of the functionality it still has. I don't have any information about when that might happen, but it almost certainly has to happen at some point, perhaps when Sims 5 shows up. (If it shows up.)
What you might prefer to do is create a blog and/or use a photo-sharing site to store your images. If you want ideas for how people present and share their games, this is a good place to browse:
https://forums.thesims.com/en_US/categories/stories-and-legacies
Some players link their blogs; others only post on that site. But either way, their content is uploaded to another site and they can choose how to present it. The other advantage of an outside site is that it likely supports a larger amount of data than thesims3.com, and if you max out the storage on one account, you can create a new one.
Having said that, if you do want to make your thesims3.com page work, try clearing the cache for Internet Explorer. Even if you never use it, the launcher does for some purposes. Be sure to uncheck the box to preserve data for favorite sites.
https://kb.wisc.edu/page.php?id=15141
If that doesn't help, move your entire Sims 3 folder out of Documents\Electronic Arts, start a random new save, play until your sim gets a memory, and try to upload that. The point is not to abandon your existing saves, just to see whether the new folder makes a difference. If it does, it's easy to move your existing content to that folder; if not, you'll know it would be a waste of time.