For years the standard was Genuine Fractals, but it has a different name and is sold by a different company - and that is never a good sign. I know there have been some real breakthroughs in the technology, but what is actually purchasable?
I do not know what kind of pictures you normal work with.
I use ‘Irfanview’, free, fast, good, does batch work wonderfully, etc…
YMMV
I use FastStone.
Also free.
If you’re using WinXP, try Microsoft’s own Powertoy Image resizer:
Click the Powertoys tab.
Once installed, just right click on the file(s) you wish to resize. Really quite nice.
Microsoft saw fit to make that download incompatible with Win7 and not offer one that does work. I found a third party utility that works exactly the same.
http://imageresizer.codeplex.com/
IrFAN works fine, too.
I have plenty of tools that will make the pixels bigger. I was talking about tools that will attempt to examine edges and detail and interpolate the information, like Genuine Fractals - but better. Looking around, I see PhotoZoom Pro, and there is a demo program called SmartEdge that looks very cool but is not ready for prime time, but on a web site that hasn’t been updated for years (though there are some sleezeballs selling the free download for $100)