Getting some black thumbnails when using photo album

Using Rapidweaver 5 built in photo album. Some of my thumbnails are black. I can see the image if I click on the thumbnail. Any reason for this? and is there a fix? also rapidweaver crashs all the time.

Are you using JPG images? PNG will often cause that type of behavior.

They are all JPG. will this happen if i buy a pluggin photo album?

I’ve never, EVER, had a problem with PNGs and I’ve used quite a few over the years.