We have a program called Fine Pix Viewer, but many others will do the same job.   Import and select the photos you want to re-size.    Press File, then Batch Resize.    In the box called "Way of Saving", create a new file for them to go into where it says "Save to".   Then, the crucial re-sizing bit:  change the file type from JPEG-fine down to JPEG-normal or JPEG-basic.   Both of these produce photos with tiny amounts of bytes - not much difference between them either in number of bytes, or quality, in my opinion.    Then, very important, de-tick "Overwrite" and "Delete the original file", otherwise you will lose the good quality, high byte, version for all time.    I leave the top box, called "Re-size" completely alone.   When you have done all of this, press OK and you should get re-sized photos in your new file which TAS, Farming Ads, and similar sites can process.