This sounds like a thumbnail problem.
When you click on an image file, a different image may be displayed in the thumbnail preview.
This happens due to thumbnail database corruption. Follow these steps to fix the problem.
Right-click the image file, and choose Refresh thumbnail
If that does not help, you may need to delete the thumbs.db file present in the folder where the image file is present. Thumbs.db contains the cache of the image files to preview. Note that the Thumbs.db is a hidden file, so you need to first enable the show all files option in Folder Options dialog.