How to disable image compression in Outlook

Problem:

Outlook reduces the quality of images in emails. This can also affect graphics in email signatures added by CodeTwo software.

Solution:

By default, the Outlook desktop app on Windows applies image compression to reduce email size.

Starting with Outlook for Microsoft 365 version 2109, you can turn off image compression in Outlook settings, ensuring that images in your email signatures don’t get modified and appear as you intended. However, there is no guarantee that image quality will be preserved once the email is sent. If someone forwards or replies to your email, the image quality in the thread may degrade despite your settings.

To prevent Outlook from applying image compression:

1. In classic Outlook for Windows, go to File > Options.
2. On the Mail tab, click the Editor Options button.
3. On the Advanced tab, under Image Size and Quality:
   • select the Do not compress images in file checkbox
   • set the Default resolution option to High fidelity
   and click OK (Fig. 1.).

Fig. 1. Disabling image compression in Outlook for Windows.