Problem begins when trying to upload a .jpg. Some .jpg work, some don't. They all upload, but some hang at "crunching" and then don't display a thumbnail in the library. When I try and edit the .jpg I get "Image data does not exist. Please re-upload the image." If I try and insert media into a page or post it does not appear, but if I use my own <img src=...></img> tagging then I can get it to appear. The .jpg is obviously in the database.
I tried tinkering with .htaccess to raise php memory limits, and that resulted in the dreaded 500 Internal Server Error. I put this line in wp-config.php: define('WP_MEMORY_LIMIT', '64M');
I'm at a loss and turning to this great community for help.