Recently I looked for a nice and easy photo resize tool to downsize a heap of photos under Windows and found the coolest tool ever: Picture Resizer.
It is only 300k small and has an indirect parameterisation for the resize command. All parameters are given in the filename of the tool itself. You download the tool and rename according to the documentation.
E.g. Rename it to PhotoResize1280MSQ85O.exe and move the desired JPEGs per drag’n'drop over the exe file – done. The commands in the name say: resize the photos to maximum of 1280 pixels, copy the Meta data, with the Quality of 85% and doesn’t wait for the enter (O).
Than zip all resized pictures and upload the zip archive to the phtagr gallery. (And later I will merge the previews to the original photos with the DupFinder plugin.)