What JasperSoft report are you trying to change, as I can't recall any of the OOTB reports using a Logo - they do use images on the OOTB reports, just not a Logo.
For custom reports, I create a custom folder structure, including a Images folder to store things like a Corporate Logo. The Custom Reports then point to that Image. If the corporate logo changes, I just upload a new copy of the corporate logo to the Images folder, using the same name. Subject to the dimensions of the image not changing significantly, then all reports using that image don't need to be modified.