When the image resolution on Danbooru differs from the image resolution at the source. The following two tags can be used with this tag.
height_source <= height_danbooru and width_source <= width_danbooru
height_source >= height_danbooru and width_source >= width_danbooru
(height_source > height_danbooru and width_source < width_danbooru) or (height_source < height_danbooru and width_source > width_danbooru)
This tag implicates md5_mismatch (learn more).
The following tags implicate this tag: source_larger and source_smaller (learn more).