Email Signature Images Loading Occasionally

Question

Hi all! Having an issue with Outlook email signatures. My team switched over to new email signatures which include a few images, including the company logo and social media icons. We've been regularly noticing that when we're responding to emails, if we scroll down to previous emails in the thread, one or more of the images are not loaded. It's different images each time, even for the same person--sometimes the logo isn't loaded, sometimes it's a social media icon.

All images have been scaled down to a low file size (<100kb), saved as a JPEG, and inserted as an inline image in the Signature feature of Outlook. Could anyone point me to what the underlying issue is here?

Answer 1

When you scroll through older messages, Outlook sometimes doesn’t re-download or render all embedded images, so you see missing logos or icons. Since each email in the thread is stored separately, different images can fail each time.

Most likely causes:

• Outlook image caching glitches
• Images stored as hidden attachments (even if inserted inline)
• Security / external image download settings
• Thread length — older messages are more likely to show missing images

We reduced this by generating signatures via MySignature, where images are inserted in a cleaner, more consistent way, but Outlook can still occasionally cache oddly in long threads.

Answer 2

We're seeing this exact thing in Outlook, however when opening the same email in Outlook Classic, the signatures aren't rendered as JPGs and links work correctly.

We can't force users to use outlook classic and so are stuck waiting on a solution from MS or Exclaimer.

Answer 3

We have this across multiple customers. I've been advised of the following from Exclaimer. Fingers crossed Microsoft fix the issue.

The issue you have reported here has been passed on to our engineering team. We have found that Microsoft is taking a little longer than usual to process the images in your signatures as they are inserted into your emails, which in turn causes the warning you're currently seeing. Whilst we continue to look into the warnings further, we can suggest using "hosted/linked" images instead within your signatures. Hosted or linked images aren't embedded in actual emails or signatures, and should not cause the reported warning to appear when sending emails with client-side setup.

However we've found that when replying to messages with images from the other parties signatures displayed is causing the same delay.

Answer 4

Dear @Fiona Mason, 

Good day! Welcome to Q&A forum! 

To understand the situation better and provide you with the most suitable support, could you confirm the following information: 

• How long has the issue been going on? 
• Are all the affected users using the same version of New Outlook? They could check it by: Go to New Outlook > Settings > General > About Outlook 
• How were the images added to the signature, via copy-paste or inserted using the “Insert Picture” tool? 
• Are the images hosted locally or linked from a web URL? 
• Could you provide a screenshot of how the emails with the missing images look like so I could have a visual reference? 
• Are recipients seeing the same issue, or is it only visible to the sender?

Your confirmation would be very helpful! 

I have tested sending an email with an image in my signature (in Settings > Account > Signatures > Insert the image using the "Insert Picture" button) and both I (the sender) and my colleague (the recipient) could see the included image. (It was a .png format picture) 

From the recipient's side: 

From the sender's side: 

In the meantime, kindly try the following suggestions to check what might have caused the issue: 

• Test with PNG Format 
  • Convert one or more signature images to PNG and reinsert them 
  • PNGs often render more reliably across email clients 
• Reinsert images as Inline 
  • Open Outlook Signature settings 
  • Remove existing images and reinsert them using Insert > Picture > From File 
  • Kindly avoid drag-and-drop or copy-paste from other sources 
• Avoid linked images 
  • Ensure images are not linked from external URLs 
  • Linked images may be blocked by email clients or firewalls 
• Test on OWA (Outlook Web App): Try switching to Outlook Web App and test if the issue persists 
• Send test emails 
  • Create a test email with the signature and send it to:  
    • Yourself 
    • A colleague using a different email client 
    • A webmail account (e.g., Gmail) 
  • Compare how the images render across platforms 

Kindly let me know when there are updates or if you need further assistance. Any updates you’re able to share would be really helpful. I appreciate your time and look forward to hearing how things are going! 

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