I decided to introduce you to a wonderful image viewer, it also serves as a converter. I use this program myself, I am quite happy, I will write right away that I do not need much in this regard, I look at images, edit them easily, that's basically it, so I am happy with everything and recommend downloading XnView  from our project. If we consider the operations that you can perform with pictures, it is worth noting the ability to crop them, change the size, adjust the brightness, gamma, and so on, print, there are built-in filters that you can also use.

I forgot to add about adjustments and filters, you can apply all these operations to a large number of files at once, that is, the batch mode is present and it is configured in detail, I really like it. You can also set presets and save them as scenarios, and you can use them at any time you need. Of course, in the main window you can preview images, that is, their reduced copies will be displayed, there is the ability to automatically create file lists, copy and paste information from the clipboard, even viewing non-graphic files is present, for example, text files.

If you make a list of supported formats, it can take a huge amount of time, I recommend just going to the official site, it is really huge, more than four hundred, so think for yourself. Additionally, you will get support for working with your scanner, you can create HTML pages with graphics, there is a simple tool that counts the number of colors in an image. 

XnView activation key file is present in the archive, but you can use it for free and without registration, most users will not notice any inconvenience, so you should not worry much about the full version, but who really wants, the keygen in the archive will help you perform the treatment without problems. In general, the software can also capture a picture from the desktop and set it as wallpaper, and you can also download a separate utility to use the program's functions through the command line.

The interface is as simple as possible, registration is not required for most, in general I like everything, I hope the program will be useful to you too, enjoy your use