ArcMap Raster Edit Suite (ARES) is an addin for ArcMap 10.x that enables value editing of single pixels on raster layer. This is an open-source software and the project is hosted at GitHub and published at SourceForge as well.
This addin only works on ArcMap 10.0/10.1/10.2/10.3.
A detail user guide could be found at: ArcMap Raster Edit Suite
Download
The listed packages are stable releases and may not include up-to-date features. To download latest version, please visit the project page.
Installation
Simply double-click the RasterEditor.esriAddIn in the package and ArcGIS AddIn installation wizzard will guide you. for more detail, check the wiki page Install and Uninstall.