If it helps any at all, I have begun compiling my own actors images (I do include your releases also). Right now, I'm primarily fixing those images that are already available to correct aspect ratios and to include better "head shots". 99% of my images also are at the maximum allowed of 300x450 for tMDB (this does not mean all images included in my download are...I still have about half of them to go through and rework).
Right now, I'm a little over 3000 images and have another update that will include about 300 more (in a couple of days). I get all of these from Google Image searches and crop/resize to fit. I can't speak for any copyright issues, so if that is a problem, don't include them.
Anyway, you can get the base download in my downloads section here
(107MB for the base file). Updates have been around 10-20MB, but none are available right now. I'll probably put one out tomorrow since I don't work on any of this over weekends.
Anyway, hope it can help your project or anyone else needing actors images.