MS1862 Item #14 states that it is of Captain Downs of Company H. This seemed straightforward, as there was an Edwin C. Downs, first a Captain, then promoted to Major in February 1864. He resigned in April 1864. Major Downs authored a book on his 20th Ohio service, the link of which is on the 20th Ohio summary page. The colorized photo is at left, the original is just below and the descriptive writing on the back of the photo (Item #15) is below that, stating he was in Company H.
However, there is a second Captain Downs, later Major shown as Item #6 in Folder Two and again in Item #28 and it is a different person. Based on the identification in Folder Two, Item #28, I believe this photo to be Edwin C. Downs and the other photos to be William G. Downs.