I use widgetsoid to add a 'trigger media update' button...
Its not a case of the media needs updating the phone just won't recognise the picture is there when I try and view it
I did a test
I took a picture with the camera, it works fine, I can view it in gallery, I can pick it as a wallpaper on the wallpaper selection screen and I can use filer, navigate to the folder the picture is in and it's there and I can click it and it opens
I then copied the picture on to the computer made sure it opens and then deleted it from the phone
Then copied the picture back into the exact same location and now it won't open, cant see it in gallery or wallpapers, navigating to the dcim folder with Filer and clicking on the picture and it's just a black screen it just won't work