Png images getting corrupted while uploading to s3

Png images getting corrupted while uploading to s3. same upload flow works in case of jpg/jpeg/pdf Steps we are following to upload files on s3 a. creating signed url (In which we are giving the location and document type) b. we are uploading the document on provided url we observe in case of png files size of the file getting increased. We are using amazon s3client (javaSDK) to upload the document which takes in signed url as the parameter