Lightroom how to change folder cover photo?

In the Library module when browsing through folders I would like to change which photo is displayed when I hover or click on a folder. I'd like to select a photo which describes the contents of the folder in the best way. I've tried re arranging photos inside the folder and sometimes the cover photo changes but most of the time it doesn't, any ideas?

Select the photo you want to be first and hit F2, Rename Photo. Select 'Custom Name - Original File Number. If your files start IMG make the text _IMG. If they start with _MG type in __MG (two underlines). Now go to View > Sort and set it to Filename.

Thanks, works great

Just remember that the underscore character "_" denotes the AdobeRGB colorspace choice in the Canon filenaming structure on-camera. That is, if you shoot in sRGB (by choosing that colorspace on the camera menu) then the filenames the camera generates will be "IMG..." - if you shoot in AdobeRGB, the filenames will be "_MG..."

kirk