[jedacandy]

You can try:
Check if your file is locked. If it is, unlock the file and try again.
Try creating a new document and see if you can move images within the new document.
If you are using "Web Layout" view mode, try switching to a different view mode, such as "Print Layout".
If you are using a shared document, check if you have editing permission for the document.
Try copying and pasting the images to a new location (my location) within your document instead of dragging and dropping.
If none of these methods work, you can refer to the help documentation or contact the software provider for assistance.