Best way to interploate my pictures

> Does there exist a programm which can interpolate my size of pictures without loss in a batch process in a little bigger size?

Increasing the size of an image is never going to be lossless in the sense that you're adding to the pixel count, not subtracting.

There are a lot of different algorithms for resizing images and which one works best depends on the image.  However the general bicubic resize available in most ( maybe all ) image processing applications works reasonable well.

If you're looking for a general purpose batch processing application then try Phatch ( which is free ).

http://photobatch.stani.be/

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StephenG