Re: cannot open jpg files?
Try resetting your preferences in Photoshop (press ctrl + alt + shift right as you start the program. When asked whether youw ant to delete the preferences, say "yes".) You'll have to be quick- if you don't get the dialogue then you haven't reset the prefs.
Re: cannot open jpg files?
If you are using Windows XP check out Powertoys for Win XP. There's a little tool there called pic resizer that (once you download it) integrates itself into your right click box and allows you to resize right in your my pics folder. Another great tool is Easy Thumnails. It's an extremely easy little tool that makes your pics thumbnail size for easy insert of pics in your E-mails. Having said all that I wonder if it isn't the resizing but the mail server you use. For instance I find you can't send a pic with Incredimail without first inserting a backround. Have you checked your sent box to see if it looks fine there? Hope I was somewhat helful.
Re: cannot open jpg files?
open windows explorer --> tools --> folder options --> file types. change them individually for each extension.