ShareX

ShareX is a screen capture and basic graphic/picture/image editing program that is open source and mature and popular.

The last version that supports Windows XP is v12.0.0.

They explain the reason they ended support and background here: https://github.com/ShareX/ShareX/issues/3201

I'll quote that discussion here because it is of general usefulness.

Jaex commented on Mar 19, 2018 •

We were using .NET Framework 4.0 for a long time because it was the last .NET Framework version which supports Windows XP. Because .NET Framework 4.0 does not support TLS 1.2 we are now forced to upgrade the .NET Framework version. Recently GitHub removed support for weak cryptographic standards and because of this ShareX auto updater which relies on the GitHub API to check for updates now only works if you have .NET Framework 4.5 or higher installed. In future, more and more services will drop support for weak cryptographic standards and make TLS 1.2 necessary. Because of this we have no choice but to upgrade the .NET Framework. Unfortunately because of this, ShareX 12.0.0 will be the last update for Windows XP and Windows Vista users. Upgrade of .NET Framework is also going to give us more technologies to work with and it is better for the security of users. We wanted to upgrade our .NET Framework version for a long time and it has now become necessary to do so. Windows XP and Vista users can still use ShareX 12.0.0 but they won't receive auto updates anymore. Unfortunately in the Steam build we are unable to stop Windows XP and Vista users from receiving updates so you must use desktop version if you are a Windows XP or Vista user. If you are using Windows 7 or higher but don't have .NET Framework 4.5 or higher installed, you can download the latest ShareX setup manually and setup will automatically download necessary .NET Framework and install it.

So, basically, as the world upgrades SSL/TLS to 1.2 (and beyond) and disallows earlier, insecure versions, Windows XP runs into more problems, because WXP doesn't have support for TLS 1.2.

ShareX website: https://getsharex.com/

ShareX downloads page: https://getsharex.com/downloads/

GitHub downloads page: https://github.com/ShareX/ShareX/releases

Last WXP version release: https://github.com/ShareX/ShareX/releases/tag/v12.0.0

Last WXP version installer: https://github.com/ShareX/ShareX/releases/download/v12.0.0/ShareX-12.0.0-setup.exe

Last WXP version portable: https://github.com/ShareX/ShareX/releases/download/v12.0.0/ShareX-portable.zip

PortableFreeware entry for ShareX: https://www.portablefreeware.com/index.php?id=2409

PortableFreeware forum discussion thread for ShareX: https://portablefreeware.com/forums/viewtopic.php?t=20412