You may use the free OneShot for Windows program to annotate images, for instance by adding text or arrow icons to them.
If you use a screenshot tool like SnagIt or one of the free screenshot taking alternatives, you may have access to annotation and image editing tools already.
The same is true if you use an image editor like GIMP, Paint.net or Adobe Photoshop. Image editors are powerful, but they may also be overkill depending on what you want to achieve.
Most editors are quite large and at least some features are difficult to get right when you are using them.
OneShot is a simple image editor that offers similar functionality as the image editing component of screenshot programs.
You can load an image or capture a screenshot, and use the provided editing tools afterwards to edit the image.
Available tools include adding arrows and various shapes to the image, adding text and lines, or using the cropping tool.
This is not a sophisticated image editor that supports layers, effects and all the advanced features that editors ship with these days; OneShot is simple, and that is definitely something that is attractive to users who don't require a full blown image with thousands of options.
Then again, the program may be too simple in some cases. You cannot drag and drop images to load them for instance, but need to use the load option or screenshot option to do so.
There is no zoom as well so that you end up with only a small part of large resolution images visible on the screen (depending on the screen resolution of course).
With all that said however, it may still be useful as an editor to annotate screenshots for instance, or to quickly add some text or shapes to an image before sharing it online.
OneShot is a basic image editor for Windows. It is lightweight and open source, and compatible with all recent versions of the Windows operating system.
The last update dates back to August 2015. This is an indicator that the program may have been abandoned by its author. It did work fine however on a recent Windows 10 Pro system.