Aliasing of Static Images

I filmed a presentation where most of the content was slides scanned from old books and catalogs. To improve viewability I took the presenter's powerpoints, wrote them to .pdf and then individually scaled them in Photoshop. I then went into to each slide and saved the individual images as separate images (he had them all in .jpeg so I am stuck with that). It didn't look bad inside premiere but once I export it to an .mp4 the old images with lots of lines tend to crawl and its quite distracting. You did a little test video on the first slide:

https://vimeo.com/63505591

Anyone know the best way to stop this before I jump into editing. I don't have access to the original documents--just the scans that were embedded in the slides. Also since there are 80 slides I am hoping the suggestion won't be something like "rescale all 80+ slides."

Thanks for any suggestions.