I run a 22 inch for my master machine but frequently connect it to my 32 inch tv. Larger resolutions do require larger images. For example, if you have an 1024768 image, that will take up the entire screen on a non wide screen 15 inch monitor, but put that onto a 22 inch and the image will be MUCH smaller. Try to put that as a background and it'll be blurry as crap. Higher resolutions and larger monitors are better, but if you've been living with a 15-17 inch for quite a while, it'll take some time to adjust to the higher resolution.
the image would only be smaller if the bigger monitor is set to a higher resolution. otherwise, if you had a 26" monitor set to 1024x768, the image will technically be the same size, but the screen will stretch it due to the inch difference. and as LBTL said, it will look horrible.
@ Lillefot: basically the way montiors work on a size-resolution scale, is the bigger screen size you get, the higher native resolution it is going to have.
example, a 17-19" monitor will have a native res of 1440x900, a 22-24 is typically 1680x1050, and 27+ will be 1900x1200.
regarding things like pictures, it will depend on what resolution they were taken in and what resolution your montor is running in. and the higher in res you go, the smaller things become.
for example. say you took a picture at 1440x900, and your monitor was set at that res with 1440x900 as its native. the picture on your PC will fill up the entire screen with no quality loss, as the picture is in exactly the same format as the monitor. on the flip side, if you took one at 1440x900, and your monitor was set to 1900x1200. there would be no quality loss, but the image on your PC would be much smaller, due to the picture res vs montior res. if you then lowered the monitor's res to 1440x900, the image would become blurry and distorted, because the monitor would not be running in its "native" resolution, therefore stretching the image.
"Native" resolution is a specific res set for monitors that LCDs typically only look good in. hence why different size monitors have different native resolutions. you can run a monitor in something other than its native, you will just get a stretched, distorted and bigger image.
CRT monitors do not suffer from this. they will look good in almost any resolution. the downside though is CRTs are huge and bulky, hence why they have become unpopular in favor of LCD/Plasma screens.
and regarding HDTVs. the average HDTV under 40" will run in a native res of 1366x768, unless it is a 1080p screen. this is much smaller than the majority of monitors out there. but it is a much bigger screen size running at that res, so it is quite desirable to use HDTVs as PC monitors.
sorry for the long post. felt like explaining it as best as i can xD
