Irfanview is a powerful and fast full multimedia viewer for Microsoft Windows.
It was originally born as a graphic viewer, but as time went by and different plugins were designed, it developed into a powerful tool to view your media files whatever the format they are.
Its small size and the possibility to be launched without installation, makes Irfanview the Swiss Army knife of media viewers.
Irfanview can even be used as a slideshow player or thumbnail viewer for your image records no matter the format. In some cases, you wil have to download the corresponding plug-in for viewing some very specific or proprietary formats.
Moreover, the program allows you to convert among different formats or perform elementary operations like rotation, conversion between colour depths or even more complex adjustments as brightness/contrast, size reduction/enlargement, etc, all this for a single file or during batch processing.
Anyway, don't worry because the additional plug-in package will cover 99% of your needs.
Ifranview supports many languages.
Its best feature is tha it´s completely free for non commercial use (whereas it will cost $12 if it is going to be used for commercial purposes)!