[Vincent Rosati] “I’m thinking you might have allowed Photoshop to be the default viewer for JPEG files, on your system. I’m not sure how to change this setting on a Mac.”
On Mac OS X, Photoshop claims the right to open any file that was saved by it… without changing the default application for the file type. My guess is that it embeds some extra information in the file that the OS uses to determine that the file was saved by Photoshop.
You can right click the file and select another application from the “Open With” contextual menu to open the file in another application this one time only.
You can also select the file and go to File > Get Info (cmd-I) and change the selected application in the “Open with:” section of the dialog to something else (you can also tell the OS to open all files of this type with the specified application).
However, I’m almost certain that your file is a JPEG and will open properly on the destination computer (especially if it’s a Mac, since Preview will even open layered PSDs… it just won’t allow you to edit them).
If you’re still concerned then you should use the “Save For Web…” option in Photoshop since this doesn’t embed the additional information and produces a ‘generic’ JPEG (and produces smaller file size).
[Vincent Rosati] “It might help to set your OS to display file extensions (again, not sure hot to do this on Mac).”
To do this on a Mac, first make sure you’re in the Finder, then go to the Finder menu and select “Preferences…” (or press cmd-,) go to the Advanced tab and check “Show all file extensions”
Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA