Inpainting doubles the image size

[Xelvoren]

Even if I inpaint a few pixels and download the processed image, the file size is doubled. I believe this is because when I input jpg image it gives me a png image with .jpg extension in the file name. How can I fix that?

Model: Tried both lama and mat
Device: Cuda

[doaortu]

I also experiencing this behavior,
initial image size is around 800KB,
after inpainting it jumps out to 3,5MB ,
input image and output image is both jpg
resolution 1920x1080