How to batch rename embedded (linked) textures in a scene? is there a way to batch rename all textures that are used by the all objects in a given scene? Background of this question is as follows:

I'm creating a set of models that all will be textured (diff, roughness, normal), and all textures will be of 4k size.
After creation, i want to have a copy of the 4K textures in 2k size. Therefore, i export all textures by using "File" --> "External data" --> "Unpack all into files". Then, i use irfan view to batch resize and rename all textures, giving them the suffix "_2k". But when i re-link the files, the file connection in the shader nodes is lost. They need to be re-linked manually. Doing this manually is ok for a small amount of textures, but this time i will have about 100 textures.

So, how can i achieve to rename all textures without loosing the connection to the shader nodes? Some advice will be very helpful. 

Thank you in advance!
This question was answered at blenderartists. See the solution with a phyton script here:

https://blenderartists.org/forum/showthread.php?441069-How-to-batch-rename-embedded-(linked)-textures-in-a-scene

Thanks to the users Photox and MartinZ for help!