i use icons for labels, but i saw this website: www.fontello.com
where you can create font with icons.
But when i create font with icons it is bigger than a
Good question. I am currently experimenting with Fontello and font icons to see if it's a viable approach.
It's a viable approach. I have used font-based icons in production applications and tested on nearly every popular browser/device (Fontello has examples which even support IE7). I have only good things to say about Fontello, but you can use any tool that you want.
Font icons can scale to any whatever (proportionate) dimensions are desired and work on any pixel density. If you look at your site on a high density display (such as Apple Retina, and increasingly popular on all mobile devices) there is an enormous difference between a raster format (like PNG) and a vector format.
You can define all icons in a single file (like a sprite), but unlike a sprite you don't have to worry about the dimensions of the items within the file. Furthermore, you can scale each item independent of other items in the file.
Considerations
These considerations are probably less work than using sprites or creating both PNGs/SVGs for every icon.
Keep in mind that a font icon does not contain any color information. However, you can style it as you would any other text. This includes using ARGB colors and applying more advanced CSS effects as pointed out in the comments.
Regarding file size, keep in mind that a browser will almost never download all 4 font formats. Done correctly, usually only one will be downloaded.
An alternative approach is to use SVGs (not SVG fonts) for icons. Browser support for SVGs is less than that of @font-face
, so you will need a raster fallback.