I want to compile a slideshow with an audio soundtrack on iMovie. The images I want to use were originally slides, which I have scanned onto the computer and imported into iPhoto as JPEG files. However, when I open iMovie, they don't register in the photos browser, so I can't drag and drop them into the Project Window. All the other JPEGs I have in iPHoto will drag and drop perfectly - it's as if the Mac knows which ones I want to use and is playing some stupid game with me!
You may already have tried this, but open iPhoto first before opening iMovie. I find that if I have them both open together and then add some pics to iPhoto, they will not immediately register in the iMovie Photo pane. My trick is to click on several different albums in iPhoto, then return to iMovie - generally (after a few attempts) iMovie will recognise the new pics. Failing this, it's best to close iMovie (and probably iPhoto), then re-open it. Note that you don't have to have iPhoto open to be able to access the photos in iMovie's Photo pane.
Open one of the scanned images in Preview and "Save As" a JPEG. Import that into iPhoto and check if iMovie recognises that new saved version. iMovie - and sometimes iPhoto - won't always recognise scanned images from certain scanning software and 3rd party imaging programs. I find this particularly with panoramas I create using a program that stitches several photos together (i.e., PanoramaMaker that came with my Epson printer). In my experience, an image saved in this way in Preview will always be accepted by other Apple programs that utilise images.
If this trick solves the problem, you'll have to perform it on every scanned image unfortunately.
I am wondering if anyone has found the answer to this post. I tried opening the file in Preview, saving it as a jpeg. Still it didn't work. Also the idea of dragging a file folder containing the files into iMovie did not work either.