size of PowerPoint slides to convert to .jpg files

I would go with 26.25 x 33.75. I think you will be fine with that size.

I am making a book of family photos to give as gifts for my family. I am using PowerPoint as suggested by the website. As suggested, I made the page size three times the size of the book (8.5 x 11) I noted on some of the blog that it was suggested that I add 1/4" to each dimention to aviod a white line around the page (my pages have a black background) Should I add 1/4" to the finished size (25.5 x 33) or should I make it 8.75 x 11.25 and then multiply by three (26.25 x 33.75)

I also wondered if I should make the added border larger for the 11 inch side, since adding .25 on each side will make the page proportionately larger on the 8.5 inch side.

I know that this is picky, but want it to turn out right.