Freeware utility for Windows. It can be resized to several pixels by several pixels. Small border. You can drag the image around if the resizable window is of different size, just that it's not visible while dragging, so you might think it's not the case at first.
Zoom in or out by pressing or -. Press Alt-C to close multiple instances if they're opened.Right-click to see image filename and get more functions (copy the location, copy the image, save as, view using system viewer, and edit using system editor).