PSE 9 Organiser Thumbnail question

Question

I took a lot of photos at a neices wedding using a Canon EOS 350D. I use Photoshop Elements 9 as my editing software and in the organizer a significant number of the thumbnails come up as a grey bevelled plaque featuring a daisy and an exclamation mark in a blue triangle. I've spent ages searching the Adobe manuals & website and cannot find a reason or explanation of the thumbnail. At first I thought it could be related to size but a lot of photos that are larger display the correct thumbnails. I've tried updating the thumbnails using the Edit menu but that doesn't achieve anything. Does anyone have any suggestions? TIA Glenys

Answer 1

Searching the Web for that icon's description turned up a couple of posts in this forum.  Apparently the original image is too large for a thumbnail to be generated.  No further explanation as to whether it's the image dimensions or the file size that's too large -- one of the messages had a link to an Adobe Knowlege Base article, but that link is now broken.
Found this in the PSE9 release notes:
function(){return A.apply(null,[this].concat($A(arguments)))}
Organizer thumbnails:
If an image has been rotated in an application other than Photoshop Elements 9, update the thumbnail before printing or using the image in a creation to ensure that the images appear properly rotated. To update the thumbnail, select the image(s) and choose Update Thumbnail or Update Thumbnail for Selected Items in the Edit menu.
Some TIFF files and files that use uncommon color profiles may appear black or as generic thumbnails in the Organizer. To fix this, select the file, and choose File Export As New File(s). This will save the file with the supported set of file tags required by the Organizer to show the thumbnails.
Very large files appear with generic thumbnails. For example, panoramas created with Photomerge Panorama return multiple layers, which, when saved, creates very large files. To make thumbnails visible in the Organizer, consider saving panorama files as flattened JPEG images
Files that are not supported in the Organizer look like broken thumbnail icons. You can import these files by saving an album containing a file in an unsupported format, using the Photoshop Elements Editor, or importing files not supported by the Organizer, using Premiere Elements.
Ken