ShareX is a free and open source program that lets you capture or record any area of your screen and share it with a single press of a key. It also allows uploading images, text or other types of files to over 50 supported destinations you can choose from.
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Pro Freezes screen when you capture
When you enter a capture mode, the screen content is preserved as it was when you started capturing by default. However there is a special "Light" mode where the screen does not freeze.
Pro Allows uploading to a vast number of different services
Designed as file uploader in the first place, ShareX supports overhelming amount of services for you to upload your files to and the list is expanding.
Pro Free and open source
You can choose what shortcut key to bind your command to, as well what host it uploads the file to.
Pro Can capture video too
Apart from still images, ShareX allows the user to record unlimited video with all the options available for normal image capture.
Pro Capturing (screen, video, a window, etc.) with annotation + automation
Capturing (screen, video, a window, etc.) with annotation + automation makes for some powerful workflows.
Annotation is key for research on any project size. Capturing screenshots, editing them ("annotating"), converting to a PNG, removing the background to make a transparent version, saving to google drive, creating large+med+sm sizes, uploading thumbnails, is an example of a workflow you could create. The list goes on...
You'll find the same strength & depth in features for image handling also for text, videos, other files by type, and on and on..
Pro Has an editor
Even though it's the Greenshot Editor, which is another tool to capture screenshots. It's the best choice take advantage of an existing tool.