Typeset all the pages with the given translations, do not change any wording. When saving the pages, do a Save to the web as a PNG-8 Perceptual w/diffusion, 64 colors and 100% dither - Depending on the manga you may be able to go as low as 14 or as high as 25. Just make sure it is clean without looking too pixelated. Keep the setting the same throughout the entire chapter.
by the way, i just want to know, but why you renamed the pics? i dont see the point of doing it also, this is one of MUST things for typesetters to keep the page numbers right. it'll be a disaster, if a typesetter messed the page numbers. im just curious.