Replying to Uploading Pics

I have some pics that i want to put on the site, but i don't know how to get them into the right format. Some are JPEGs, but they are to big. Some are sequences that I took off my camcorder and put together with Publisher. I've tried putting both types on, but they didn't work. Any help would be appreciated. If you are confused because you have seen this post elsewhere on the site, don't be because I posted it a couple of times. I am just really helpless when it comes to stuff like this. Thanks!