Convert BMP to JPG

JPG or PNG for a BMP?

Both are much smaller than BMP, but they suit different pictures:

When the picture is a photograph and will be emailed, uploaded or put in a document, JPG is the practical choice. Flat artwork is where JPG struggles: it adds faint ripples around hard edges, and the file may not even be much smaller than a PNG.

Export settles close calls: its size estimate updates when you change Kind of file between JPG and PNG, and when the PNG is barely bigger, it is the one to keep.

From megabytes to kilobytes

Uncompressed pictures add up quickly. A letter-size page scanned at 300 dpi is about 2550 × 3300 pixels; at three bytes a pixel, that is around 25 MB as a BMP. As a JPG, the same page is a small fraction of that.

Two settings in Export decide the final size:

• Quality, from 30 to 100. 88 is the starting point and suits most photos and scans; go higher for fine print, lower for previews.
• Size: the full size, or 3840, 2560, 2048, 1920, 1600, 1280, 1080, 800 or 512 pixels wide when the picture is wider. A scan you only need to read on screen rarely needs its full width, and a photo for email looks good on any screen at 1920 or 1280.

The line under the settings gives the result's dimensions and about how many KB or MB the JPG will be.

Scans and old picture folders

Some scanner software and older Windows programs save BMP by default, so archives of scanned photos, letters and drawings often sit on a disk in a format that is awkward to share. A JPG copy of each one is easier to email, to upload to a photo service, or to put on a phone.

The original BMPs stay where they were, so you can check the copies before tidying up. Saving a picture on its own passes through the Windows Save window, a chance to swap a scanner's numbered file name for one that says what is in the picture; Save all as ZIP keeps the names as they are.

If you would rather keep every pixel exactly, PNG does that, usually at a size between BMP and JPG. And if scanned pages belong in one document, the PDF Editor turns pictures into a PDF.

Making a scanned page easier to read

A scan straight from the glass is rarely as clear as it could be. A few changes in the Photo Editor before you export the JPG help a lot, and none of them touch the BMP:

• Straighten it with the Crop tool (C): drag outside the box, or type the Angle, up to 45 degrees either way in tenth-of-a-degree steps.
• Crop away the uneven edges a scanner often leaves, and the empty margins, in the same step.
• Darken the text with Levels or Brightness/Contrast from Image › Adjustments: a little more contrast and a touch less brightness make faint print easier to read.
• Go gray with Black & White for text pages, which drops colored tints from yellowed paper. See black and white photos.

Then press Export and keep JPG. For text, a Quality of 90 or more keeps letters clean.