Clarifying quality

Can the moderators please clarify their definition of quality.
I've tried a couple of times to upload a picture which is ostensibly the same size as an existing one but with a much larger file size (please forgive any erroneous terminology, I'm no photographer!). In cases where I've previously downloaded the 'smaller' picture, I've noticed that the quality is often quite poor in comparison, with areas of pixelation etc. What finally prompted me to ask is my discovery of a picture for Ratatouille which has a file size ten times larger than the existing picture (2114 X 1028 but only 141kb, whereas mine is 1.41MB). Surely this is higher quality, it certainly is to the naked eye but I doubt it would be approved. Thanks.

The word you're looking for is resolution.
When that is the case, what I generally do in the tag space, is state that it's a higher quality update to the preexisting image.

Sorry to be contrary but isn't resolution the actual size of the picture in pixels (i.e 2114 X 1028, in my example above) not the file size, as in kilobytes etc. As I've described in my original message, the 'measurements' are the same but there are lots more kilobytes! When I tried to upload a few Bronson pictures that, to the naked eye, were far better quality, although the same size in pixels, I did put a note in the tag space to highlight this fact but the pictures were still rejected, hence my question.

SpinnersLibrarian:
Sorry to be contrary but isn't resolution the actual size of the picture in pixels (i.e 2114 X 1028, in my example above) not the file size, as in kilobytes etc. As I've described in my original message, the 'measurements' are the same but there are lots more kilobytes! When I tried to upload a few Bronson pictures that, to the naked eye, were far better quality, although the same size in pixels, I did put a note in the tag space to highlight this fact but the pictures were still rejected, hence my question.

It's not, it's the DPI of the image makes up the resolution of the image, what you're thinking of is the dimensions.