In jee mains form my photo is 30kb n sign 20kb but i hvnt adjust the dimension will there will b any problem regarding rejection of form?

There would be no problem in your case but check this:

• The scanned images of photograph and Signature should be in jpg/jpeg format only.
• Size of the photo image must be greater than 4 kb and less than 40 kb.
• Size of the signature image must be greater than 1 kb and less than 30 kb.
• Dimension of photograph image should be 3.5 cm(width) x 4.5 cm(Height) only.
• Dimension of signature image should be 3.5 cm(length) x 1.5 cm(Height) only.

If you have paid the fees then you can modify your photo in month of january.If you have not paid your fees then you can still change or correct the details