If it is a one-off, I would download the months' free trial of Lightroom, import all the photos into a catalogue, then export them to a different directory using a quality setting of 100%, and specifying a file size limit of 10mb. Lightroom will then adjust the quality of any that exceed that to suit, but keep the original dimensions the same.
There's also a program called advanced jpeg compressor which I use when I really want to heavily compress files, e.g. for creating thumbnails, reduced size versions for on-line galleries etc. It took a while to work out how to create a profile for batch processing. It's quite quick - take about 3 minutes to compress around 300 full size images to 800px wide, stripping out the EXIF data and compressing to about 70 - 100 Kb each. I think it does have a lossless compression option as well, but I've never used that. Think the cost was about $30 about 4 years ago and it's saved me more than that over the years in the time saved uploading batches of photos to websites/FB etc, before fibre broadband was available in our area.