The file name you were trying to upload has been blacklisted because it looks like a MediaWiki thumbnail image name. (Such thumbnails have names with a prefix like "800px-" followed by the name of the original file.)
If you were trying to move this file to Commons from another Wikimedia project (Wikipedia, Wikibooks, etc.), you probably downloaded the thumbnail image instead of the original file by mistake. Please go back to the original file description page and click on the "Full resolution" ("Original file") link to download the full-size image.
If you have some reason for uploading a file with this particular name, or if you receive this message when attempting to upload a new version of an existing file, please let us know at Commons:Administrators' noticeboard or directly at MediaWiki talk:Titleblacklist. Be sure to specify the exact name of the file you are trying to upload. Thank you.