The Firm Tools shell extension provides an interesting solution to this. It shows a miniature preview in the context menu (right click menu) and particularly handy when you are in a file open dialog of the program that lacks the image preview functionality.
The free tool is very simple to use, just download and install it, right click on an image file to see it its preview. Clicking on the thumbnail will open the image in the default program.
Moreover, there is another option. The ‘Convert to’ context command is quite impressive. You can convert common graphic formats instantaneously with it.
Converting supports most of the formats you will ever need: JPEG, TIFF, PSD, PNG, GIF, BMP, TGA, PCX, and a few others.
You can configure a few settings like preview size, print option, etc from All Programs – FirmTools – ShellExtension – Configure ShellExtension.