Posting pics direct from your hard drive are usually too big. Using a hosting pic site will automatically reduce the size and allow them to post on here. There are some free host sites, just do a search for "free picture hosting" and see what you come up with. I have been with Photobucket for many years and am grandfathered in at a low rate, or I couldn't/wouldn't afford to keep using them.

I post pics from my computer on here. I open them with Microsoft Office, then downsize using "compress picture".