Why does Office apps converts JPG files to PNG?

Question

I am facing multiple issues of Word, Powerpoint and Excel files exploding in size as soon I add JPEG images in them. For instance:

• In Word, I import a JPEG file of dimensions 1620x1080px. File size: 318KB.
• I save the Word doc in DOCX format. The DOCX document size increases by 318KB. Okay so far.
• I use the Picture Correction tool to modify the Brightness & Contrast of the image, then save the file again.
• Now the DOCX file increases by 3MBytes!
• If I rename the .xlsx document in .zip, I can see in the media subfolder my picture is stored in PNG format, and has a size of more than 3MBytes! that is waaay less inefficient than the initial JPG file...

In Excel, it is worse: it seems all imported JPF image are immediately converted in a less efficient PNG file. Using the "Compress Pictures" tool doesn't help as it seem once the image has been converted to PNG, it stays in that format.

Office Version 2208, build 15601.20538 for Windows.

Any solution possible to force a specific file format when inserting a picture?

Answer 1

Hi,

I'm Sneha and I'd be happy to help you out with your question. Sorry for the inconvenience caused.

The reason Microsoft Office apps convert JPEG files to PNG when they are inserted into a document is that PNG files are a lossless image format, which means they retain all the image quality without any degradation. In contrast, JPEG files are a lossy format, which means they can lose some image quality when saved or edited.

When you edit a JPEG image in Office apps, it automatically converts it to a PNG format to preserve the image quality. This is why the file size of your Word document increases significantly after you edit a JPEG image.

Unfortunately, there is no way to force Office apps to use a specific file format when inserting a picture. However, you can try using an external image editing tool to modify the brightness and contrast of your JPEG images before inserting them into your Office documents. This way, you can avoid the automatic conversion to PNG format and reduce the file size of your documents.

Another option is to compress the images after inserting them into your documents using the "Compress Pictures" tool. This will reduce the file size of your documents by reducing the image quality, but it may not be as effective if the images have already been converted to PNG format.

If you have any other questions or need assistance with anything, please don't hesitate to let me know. It will be my pleasure to Assist you.

Best Regards, Sneha