How to flatten the image of a label on a food jar?

1. How do I flatten a JPEG?
2. What does it mean to flatten a picture?

How do I flatten a JPEG?

If you are working with a layered image in Photoshop, you will need to flatten the image before you can save it as a single layer file. To do this, go to the Layer menu and select Flatten Image. This will merge all of the layers into one layer. You can also flatten an image by exporting it as a PNG or TIFF file.

What does it mean to flatten a picture?

Merging all visible layers into the background layer to reduce file size.