the free download of Flash CS4 (good for 30 days) will allow you to import sequential
image files and export an *.avi.
the input files need to be numbered in a particular way, like
asdf0000.jpg
asdf0001.jpg
...
asdf2000.jpg
for the program to recognize them as sequential.
there's also Ulead GIF Animator.
Flash will also let you load randomly named files into sequential key-frames,
but them you have the labor of drag-and-dropping 2000 images.