Windows 7 shows image thumbnail previews in a folder but it just shows the thumbnail and there is not much you can do with it. If you have to perform some basic tasks on images regularly, like rotating and resizing then you might want to add XnView shell extension in Windows 7. The XnView shell extension adds the functionality for you to view the thumbnail preview of any image by right-clicking on that image. The image thumbnail preview is show in the context menu itself, so no extra window opens up.
You can download XnView shell extension from http://www.xnview.com/en/downloadwin32.html. The download is an installable setup file of around 900 kilobytes size. After installation when you right-click on a image file, you would see an extra item named XnShell, in the context-menu. The sub-menu of this XnShell item would show the thumbnail of the selected image along with many other options.
It has the Convert option which allows you to convert any image from and into over twenty different formats (like GIF, BMP, JPG, PCX, PNG, TIFF, TGA and many more). Just right-click on one or more images and select XnShell → Convert and you would see a conversion dialog. In this you can select the target image format and image resizing options. Then clicking on the Convert button would start the conversion.
Among other things, you can also set the selected image as a desktop wallpaper by selecting XnShell → Set wallpaper as. You are given the options of setting the wallpaper in best fit, fit to desktop, centered or tiled styles.
If you want, then you can send the selected image to the popular online image hosting site ImageShack by choosing XnShell → Send to ImageShack. This automatically uploads the selected image to ImageShack servers. You would be shown a link to the uploaded picture in your web browser after the uploading is finished. This makes uploading and sharing an image online a very easy task.
You can choose the options for XnView shell extension from the context menu options XnShell → Options. In the Options window, you can choose from an array of options. You can choose what menu items are to be shown in the right-click XnShell context menu. You can choose the thumbnail size for the image thumbnail shown in the context-menu. Typically the thumbnail size should be choose with width to height ratio as 4:3. But you are free to choose any dimensions you like.
The XnView shell extension can convert or resize not only a single image but it also supports batch image resizing or converting. So if you keep converting image formats, resizing images, rotating them or uploading them to ImageShack online image sharing site on a regular basis, then you will find the XnView shell extension a very useful tool for your computer.