Irfanview is freeware, but if you like the program you can DONATE to the project, here.

IrfanView is a very fast, small, compact and innovative FREEWARE (for non-commercial use) graphic viewer for Windows 9x, ME, NT, 2000, XP, 2003 , 2008, Vista, Windows 7.

It is trying to be simple for beginners and powerful for professionals.

IrfanView is trying to create new and/or interesting features in its own way, unlike some other graphic viewers, whose whole "creativity" is based on feature cloning, stealing of ideas and whole dialogs from ACDSee and/or IrfanView! (for example: XnView has been stealing/cloning features and whole dialogs from IrfanView, for 10+ years).

IrfanView was the first Windows graphic viewer WORLDWIDE with Multiple (animated) GIF support. One of the first graphic viewers WORLDWIDE with Multipage TIF support.
The first graphic viewer WORLDWIDE with Multiple ICO support.

Features:

Many supported file formats (click here the list of formats)

Multi language support

Thumbnail/preview option

Paint option - to draw lines, circles, arrows, straighten image etc.

Toolbar skins option

Slideshow (save slideshow as EXE/SCR or burn it to CD)

Show EXIF/IPTC/Comment text in Slideshow/Fullscreen etc.

Support for Adobe Photoshop Filters

Fast directory view (moving through directory)

Batch conversion (with image processing)

Multipage TIF editing

File search

Email option

Multimedia player

Print option

Support for embedded color profiles in JPG/TIF

Change color depth

Scan (batch scan) support

Cut/crop

IPTC editing

Effects (Sharpen, Blur, Adobe 8BF, Filter Factory, Filters Unlimited, etc.)

Capturing

Extract icons from EXE/DLL/ICLs

Lossless JPG rotation

Unicode support

Many hotkeys

Many command line options

Many PlugIns

Only one EXE-File, no DLLs, no Shareware messages like "I Agree" or "Evaluation expired"

No registry changes without user action/permission!

..And much, much more