One of the stranger changes - at least to me - made by Reilly & Britton to a book cover, happened to Aunt Jane's Nieces at Work, written by L. Frank Baum under his pseudonym of Edith Van Dyne. This was published in 1909, but for some reason the blue fabric with stars, as well as the shield with stars and stripes, was dropped from the cover in later printings - at least, the copy from 1912 that I'm showing on the right. This required the re-drawing of the lower portion of the cover image. Perhaps the publishers felt the original cover looked a little too political for a book for young girls? The story involves the nieces helping out in a friend's political campaign, so that reason wouldn't make much sense.
At any rate, I think the stories in these books are still very enjoyable!