   Image manipulations.
  Hello.I am looking for a good algorithm to resize images , down and up. I was looking at stuff like box filters, but that only takes care of integral conversion, is there something more flexible that i can look at?I got a few other but i am asking for an opninion.So far i took an indepth look at bilinear filters which are allright as well as box filters which seem to suck.Any sujestions on which ones i should look at other then these?Thx   
  Wikipedia has a lot of good info:Interpolation in generalRead this page for 1d examples, there's a brief 2d section near the bottom.Bicubic Interpolation is the "best" standard image filtering around (that I'm aware of, and that is in "popular" photo editing programs).  I would heartily recommend bicubic over bilinear filtering.  It doesn't have the linear issues so keenly shown in the first page linked (interpolation)(Bicubic interpolation fits under the heading of Spline interpolation in this article.)  Natural Cubic Spline (This includes the formula you'll need to perform cubic interpolation)If you really want to scrutinize some "higher" techniques for image interpolation (ie. non-realtime) dive into the following    ;  Hmm, if you aren't *that* concerned the general rule of thumb is bicubic for up-scaling, bilinear for down-scaling.  (or was it the other way around?) ;)Photoshop cs (I understand) has a Bicubic Smooth and Bicubic Sharp filter.  I would imagine these widen or narrow the curve of the bicubic filter.  You can accomplish similar results with a post gaussian blur or 1-guassian based sharpen.Or you can use a larger polynomial size to get a slightly smoother look.  (Sometimes it's useful in up-scaling an image to soften the interpolated values at the end (esp if you used bicubic interpolation))(Okay, I'm *really* done blabbing now)-Michael g.   ;  Have a look at the DevIL manual.  It shows comparisons between several filter types for increasing image sizes, under the heading "Filter Compparisons".http://openil.sourceforge.net/docs/index.phpEDIT: link didn't work before for some reason???