I made a flip book in .exe format and its output size is 19 MB. I want to reduce its size up to 11 MB or near. I have tried upx & mpress compressor, but it didn't help.I tried to reduce the size of pdf files to be imported and changed the quality of the pages & size too.but the output is same.

Often the problem is that the images used have not been web optimized and are their original large size. Check out that option first.

This is one instruction on how to reduce size of the file and here is another one that is about PDF files. Try whichever you think is the best one.