As of version 2, PhotoRaw implements virtual memory, which means that there is no specific upper limit on image size. Experimentally, we've imported files from medium format backs, e.g., from Phase One's 45 megapixel P45 back. The real limit on image size is practical - importing such files can take a very long time - especially on first generation iPads, the larger the file, the more PhotoRaw has to use virtual memory and the slower imports become. We suggest that you try your largest files on PhotoRaw Lite, and decide for yourself whether PhotoRaw will work in your particular situation.