Back to 'Deliverability'Outlook blocks SVG images in emails, here's what you need to know
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Are you sending emails with SVG images? Outlook recipients won't see them anymore. Since October 2025, Microsoft blocks all SVG images that are embedded inline in emails.
The rollout started in September 2025 and is now complete. Why Microsoft made this decision and what you can do about it, we'll cover in this article.
Why does Outlook block SVG images?
SVG files are different from regular images like PNG or JPEG. An SVG is actually a piece of code that the browser or email client reads and converts into an image. The problem? Attackers can hide malicious scripts in that code.
That's exactly why Microsoft stopped displaying inline SVG images. The number of phishing attacks via SVG files increased significantly over the past years. By blocking SVG images, Microsoft prevents recipients from becoming victims of these attacks.
The official announcement from Microsoft is in the Microsoft 365 Message Center under number MC1130385. This is only accessible to Microsoft 365 administrators. BleepingComputer wrote an article about this change.
Which Outlook versions block SVG?
The block applies to:
- Outlook on the web (webmail via outlook.com or Microsoft 365)
- New Outlook for Windows (the redesigned desktop app)
Outlook Classic, the traditional desktop version, already blocked inline SVG images before. Outlook Mobile still shows them for now, but Microsoft may change this later as well.
What does this mean for your emails?
If you use SVG images inline in your emails, Outlook recipients now see a blank space. The rest of your email remains visible.
According to Microsoft, this affects less than 0.1% of all images in Outlook. Most emails won't be impacted. But if you use SVG for your logo or icons? Then it's time to switch to a different format.
Difference between inline and attachment
An inline image is directly visible in the email itself, like a logo at the top or an icon next to a button. This works with a Content-ID that refers to the image. An attachment is a separate file at the bottom of the email that needs to be downloaded first.
SVG files as attachments still work fine. Recipients can download and open them. Only inline SVG images are blocked.
What alternatives can you use?
For emails, we recommend switching to other file formats.
| Format | Transparency | Quality | File size | Email client support |
|---|---|---|---|---|
| PNG | Yes | High | Medium | All clients |
| WebP | Yes | High | Small | Modern clients |
| JPEG | No | Medium | Small | All clients |
| GIF | Yes | Low | Large | All clients |
PNG
PNG is the best choice for most situations. It supports transparent backgrounds and is displayed correctly by all email clients.
WebP
WebP offers better compression than PNG at the same quality. Older email clients don't always support WebP.
JPEG
JPEG is suitable for photos with many colors. Without transparency, it's less suitable for logos or social media icons.
GIF
GIF supports transparency but is limited to 256 colors. Mainly useful for simple animations. Note: GIF files can quickly become large. Keep the maximum email size in mind.
Conclusion
SVG images in emails are a thing of the past, at least for Outlook users. Your emails still arrive, but recipients see a blank space where your image should be. Right now, this doesn't affect whether your emails get delivered. But email clients may start judging emails with SVG images more strictly in the future or even mark them as spam. There's a good chance other email providers like Google will follow Microsoft's example.
This is a good time to check your transactional emails and broadcast emails. Check for inline SVGs being used, for example as a logo or social media icons. Replace them with PNG and your Outlook recipients will see your images again.