How can compress image(jpg & png) to less then 500kb?

Question

if I have upload 10 mb image compress to less then 500kb or if I upload 1 mb then compress to 500kb
- I want to do this with programming(Java)
- image type will be either jpg or PNG
- image size will be greater then 1MB to 25MB

Answer 1

Depending on the format of the original image this may not be possible with compression alone. At least not without keeping the image relatively viewable. We need more information about the image you want to compress.

Answer 2

What file format? How about an online converter (convert to jpg...)?
I don't get your description...