Paper
If you made a disc image from a folder and burnt it, you most likely made Mac formated disc (either Extended or Standard) which wouldn't be able to be read on a PC. Now I haven't used iPhoto to burn discs, so I don't know if it can do hybrid discs (Mac & PC), but you can try this...
If you go to the File menu (when in Finder), select "New Burn Folder". Drag your photos into the newly created "Burn Folder". Don't worry that the files look like aliases (they are just placeholders, the actual files will be written to disc). When you are done loading the folder (and don't forget to rename the folder to what you want the disc to be named), burn the disc by either clicking the "Burn" button in the open "Burn Folder" window, or selecting "Burn 'Folder Name' to Disc..." via the Finder's "File" menu. Insert blank disc, and away you go. According to the dialog, a Burn Folder burn "should" be readable on both Mac and Windows.
Or...
Open Disk Utility... click New Image... then select Image Format>MS-DOS (FAT)... then select a size that can accommodate all the photos... name the image, then create it.
When the image mounts on your desktop, drag your photos into it (like a virtual HD), then unmount it. When you are done, burn it to disc with Disk Utility.
Now since this is in MS-DOS format, you may need to rename the files in the old 8+3 format (XXNAMEXX.EXT), or the files maybe truncated when viewed on a PC.
Hopefully one of these methods will work for you. It's been awhile since I've done either of these, as I use Toast for my burning needs. 😉 However, you should be go to go.
HTH
