Norbert Hoeller wrote: There are three main benefits of using ImageMagick: 1) Better scaling quality 2) Since it runs out of process, if the scaling fails (eg due to memory limits), the rest of the wiki keeps running. You just don't have a working image. 3) For JPEG images (at least in some versions), ImageMagick can scale large images without decompressing the entire file into memory/scratch space first. (GIF and PNG images still require loading the whole thing.) How much memory (or scratch disk) ImageMagick will actually use depends on what mode it's been compiled in (8-bit, 16-bit, or 32-bit pixel depth), but you don't always have to worry too much about that. MediaWiki has a switch to disable scaling of very large images: /** * Don't thumbnail an image if it will use too much working memory * Default is 50 MB if decompressed to RGBA form, which corresponds to * 12.5 million pixels or 3500x3500 */ $wgMaxImageArea = 1.25e7; You can decrease that size to keep large images from breaking the entire system... *however* it isn't applied to JPEG images due to ImageMagick's nicer behavior with them. To make it apply to JPEGs as well (eg for GD) you might have to hack out the exception for now. Probably we should fix it to check this automatically. (In current MediaWiki this is in includes/media/Bitmap.php. In older versions you'll probably find it in includes/Image.php) -- brion vibber (brion @ wikimedia.org)