This question already has an answer here:
Background is that in my lab it is common and convenient to document stuff by simply making a picture of it. Once a project is finished, I will merge these pictures into one file which I will give to other group members so they can work with it. Since these files often contain 20+ images where each image is a few Mb the PDF-File gets quite large (>100Mb).
That is why I am wondering: Is there any convenient way in LaTex to lower the resolution of pictures without having to run them through another software beforehand ?