HTML Email Signature Troubleshooting

Email Signature Has a Gap Below Images

In most/all email clients:

Solution: Add a line height style attribute to the containing table data element <td style="line-height:0px; {add other inline styles here as needed} ">

This would not work if there is text within the same <td> element but text should not be there in the first place since it should be in it’s own <td> element, separate from the image.

Only in Gmail:

Solution: Haven't found one

In testing, if you send an email from Outlook 2016 to Gmail and then back again, we haven’t found a way to remove the gap when viewing the email signature in Gmail.

email signature gap below images

Email Signature Images Changing Size

Solution: Check/Change the DPI of the image you're using in your email signature. Set to 96 DPI if you're using Outlook. Set to 72 DPI if you're using Apple Mail.

If the DPI setting on your image is not correct, you’ll end up with an enlarged image when you compose a new email.

To fix this, you will need to use an image processing tool such as Photoshop to change the DPI setting on the image. This is because Microsoft Outlook and Apple Mail scale images using the DPI values.

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email signature images changing size

Email Signature Images Aren’t Displayed at the Correct Size

Solution: Set the image height and width attributes on the <img> tag without units such as px. For example <img height="60" width="120">.

Be sure that these attributes match the actual dimensions of the image in pixels. So if your image is 10 pixels tall, the image tag should have a height attribute equal to just “10” without any units.

Email Signature Images Not Correct Size HTML

Email Signature Images Are Blurry (aren’t Clear)

Solution: Ensure your image resolution is set to 96 DPI (for Outlook) or 72 DPI (for Apple Mail) and your display scaling settings are set to 100%.

If the images in your email signature don’t look as clear as they should, there are a few things that need to be considered.

Firstly, you will need to ensure your image is high resolution so it will still look crisp and clear when scaled up on mobile devices. If this doesn’t help, check your display scaling to make sure it is set to 100%, and that your images are set to 96 DPI (for Outlook) or 72 DPI (for Apple Mail).

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Email Signature Images Being Added as Attachments

Solution: Make sure your email client is set to compose new emails in HTML format and if needed, change the email formatting on each incoming email that has been formatted in plain text / rich text format. 
Check that your mail server is not automatically converting your outgoing emails to plain text.

Sometimes your email signature will come up in plain text and not be displayed like it was when you first created it. This happens due to the email in question being composed, or converted to plain text / rich text format. When this happens, Outlook will automatically convert any images that were in the email signature, into attachments.

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Email Signature Troubleshooting

Email Signature Font Changing to Times New Roman When Sent to Outlook

Solution: Ensure you put a Non-breaking space (&nbsp;) in front of the element that is getting changed in Outlook. Also, ensure that sans-serif is not the last font in the font-family or any other font property. Always have another font as the last one, otherwise Outlook will convert it to Times New Roman.

This is an issue that has been plaguing Outlook for quite some time, and it can be a very difficult problem to fix, unless you know where to look. The versions of Outlook it affects is 2007, 2010, 2013 and 2016. This also depends on the platform you are sending the email from. For example, if you send from Outlook for Mac to Outlook 2016 in Windows, the problem likely wont appear. However, if you send from Office 365 to Outlook 2016, you will notice the problem come up.

So it’s easier to understand what the problem actually is, we will first illustrate with some pictures on the right.

Notice the difference in the fonts from the original sent email signature, and the one that was received in Outlook 2016? The original email signature was sent using Arial font and Outlook converted it to Times New Roman. Thankfully, there are a few known working fixes for this issue, but the problem is that sometimes you may need to try a couple of different fixes in order to figure out which one works for you.

Original email signature in Office 365 (this is the way the signature is supposed to look like):


This is the email signature when it arrives in Outlook 2016:


Outlook Not Downloading Images Automatically in Email Messages

Solution: Set your Trust Center settings in Outlook to allow automatic download of images in email messages.

Outlook has a security feature that is enabled by default which prevents images from being automatically downloaded on all incoming emails.

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Gmail Email Signature Too Long Error Message

Solution: Ensure your email signature has less than around 10,000 characters and you are using Google Chrome or Internet Explorer when updating the signature in Gmail.

Gmail will display an error message saying “Sorry, the signature for <your email address> is too long. Please try a shorter signature.” if your email signature is greater than around 10,000 characters. If your email signature has more than 10,000 characters, you will need to lower the character count for it to work with Gmail.

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Gmail Email Signature Too Long

Cannot Add or Edit Email Signature in Office 365 OWA

Solution: Edit the OWA Mailbox Policy permissions and allow Email signatures as a feature.

When trying to add an email signature to Office 365 OWA (Outlook Web Access) you may notice the Signature section is missing, grayed out, or you may see a message like “The option you chose isn’t available”.

This is because the feature is disabled in your OWA policy. There is an easy way to fix this if you have administrative rights to your Office 365.

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Office365 OWA Email Signature Not Available

Copying and Pasting an Email Signature Is Breaking the Formatting

Solution: Use Google Chrome to copy your email signature.

When creating an email signature in Gimmio (or any other email signature generator), you may get formatting problems when pasting your email signature into your email client. The most common reason for this happening is that your browser isn’t copying all of the HTML tables in the email signature.

For example, if you are using Gimmio with the Safari browser and you attempt to copy the email signature, Safari will not copy all of the HTML tables, and the formatting of the email signature will be broken when you paste it into your email client. The solution is to use Google Chrome when copying your email signature, this will ensure that all HTML tables are copied correctly.

Email Signature Broken Formatting

Images Not Showing up in Apple Mail Email Signature

Solution: When installing your email signature, ensure you untick the box at the bottom of the signature preview window which says “Always match my default message font” as this will turn your email signature into plain text format.

Sometimes Apple Mail might not display images in the email signature when it is shown in the signature preview window. However, when you compose a new email, the signature should look fine (with images).

Other times, the email signature will not show images at all, even when you compose a new email. There could be various reasons and ways to fix this.

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Thunderbird Has Red Borders Inside and Around the Email Signature

Solution: This is normal Thunderbird functionality.

Thunderbird will often show red borders inside and around the email signature when you compose a new email. Those borders will not be visible to your recipients, and your email signature will look normal to them.

Thunderbird Red Borders Around Email Signature

Images Disappear When Replying to Emails on iPhone or iPad

Solution: Go to Settings > Mail > Include Attachments with Replies > Always. Once changing this setting, all attachments will be included in your replies.

When replying to emails using the Mail App on your iPhone or iPad, you might notice that the images in the reply are being removed. The images are replaced with the file name instead, eg. <filename.png>.

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Outlook Sending Winmail.Dat Attachments

Solution: Set new emails to be composed in HTML or Plain Text format. Also, when sending to internet recipients in Rich Text format, ensure that "Convert to HTML" is selected.

When sending emails in Rich Text format, Outlook will add an attachment called “winmail.dat” to every outgoing email. This can be annoying and unwanted by many users.

The winmail.dat file contains all the instructions about text formatting within the email that other email clients can use to determine how to format the email.

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Winmail.dat Attachment In Outlook

Blue Question Mark Boxes Instead of Images in Outlook for Mac

Solution: To fix the blue question mark boxes in Outlook for Mac, you need to allow the automatic download of remote images. When you do this, the actual images will load, instead of the blue question mark boxes.

Are you seeing blue question mark boxes popping up in place of images in all of your emails?

By default, Outlook doesn’t automatically download remote images, and there’s a really good reason for this.

If you were a spammer that is monitoring the web server where your images are hosted, you could easily find out if an email address is a valid one just by checking to see if the image was downloaded when you sent the spam email.

This is why Outlook has this feature disabled by default. However, if you’re savvy and don’t open emails from random senders, then there’s no need to worry and it’s likely safe to allow remote images to download automatically.

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Blue Question Mark Boxes Images Outlook for Mac

Gmail Signature Has 2 Dashes Above It

Solution: To remove the 2 dashes (--) above your email signature, go into the Gmail settings and scroll down to the email signature section. From there, tick the checkbox that says "Insert this signature before quoted text in replies and remove the "--" line that precedes it", then click Save Changes.

When you install your Gmail email signature, you may notice there are 2 dashes (–) above your email signature. These 2 dashes are automatically added by Gmail in order to separate the email body content from the signature section.

Gmail 2 Dashes Above Email Signature

Email Signature Line Spacing/Table Spacing Appears Larger in Outlook

Solution: Haven’t found one.

Outlook interprets line breaks in HTML signatures as paragraph breaks, making the lines space out more than intended. For example, if you’re copying an email signature from Google Chrome, your line spacing may look different when it’s pasted into Outlook.

Unfortunately, there are no real solutions to this at the moment. The problem is related to the way that Outlook renders HTML.

A known workaround is to minimize the spacing between each line to compensate for the spacing out.


Images and Icons Are Partially Cut When Composing in Outlook

Solution: Simply send the email signature as is, this isn't an issue once the email is sent.

This is a visual glitch that only occurs when composing a new email in Outlook. Once the email (together with the signature) has been sent, the images and icons will display correctly (not cut off) to the recipient.

It appears that images/icons only get cut off from the right-hand side and only around 1 pixel in width is cut off.


Email Signature Text Wraps When Viewed on Gmail (iOS)

Solution: Design the email signature to have a maximum width of 350 pixels or lower.

An email signature with a width higher than around 350 pixels tends to text wrap when viewing on the Gmail app for iOS. This is because mobile phone screens are narrow and their viewport is much smaller than a PC.

There are other mobile email app’s that also text wrap when a signature is too wide. So, considering the size of your email signature is an important factor when designing.