You can upload files up to 100mb in the Online Print Studio, it’s best to always upload the largest original version you have available. If you are exceeding the 100mb size limit re-save the file as a hi-resolution jpeg to get below the size limit (ie a compression level of 8 or higher, or “high quality,” etc, depending on the program you are using). There is no need to either downsize or up-rez the file from it’s original data, we can make that determination on our end. If you have larger files that you would prefer not to compress, you can contact our custom studio and we will arrange an alternative.