TYPO3 Core

Im using FTP to work in the fileadmin and the problem is that image width and height doesn't update in the sys_file table. Even i replace the picture in the RTE or I reupload and replace my picture with the typo3 fileupload the sys_file table doesn't change. The problem is that for the rendering the parser add width and height to image tag and the parser take that size in the sys_file table. Thus, i got scaled images. Sometime I have to crop and replace my images, I don't want to renamed it to have it not scaled!