This article explains the recommended image sizes, resolutions, and file types to use when you add images, such as headshots and logos, to your signature in WiseStamp. Following these recommendations keeps your images sharp inside your WiseStamp signature while keeping the signature lightweight.
What dimensions should my signature be?
A few size guidelines help your signature display correctly across email clients and devices. Sizes here are given in px (pixels). A pixel is one of the tiny dots that make up an image on a screen, and it is the standard way to measure image and signature sizes.
Overall width: In the WiseStamp Studio, the signature width is capped at 500px. If you enter a larger value, the Studio reverts it back to 500px. Designing within 500px keeps your signature rendering consistently across email clients and on mobile screens.
Height: There is no fixed height limit, but keeping your signature roughly 150–200px tall keeps it compact and easy to read. If you have a lot of content, build it vertically rather than making it wider.
Columns: Keep your layout to 2 columns where possible, and no more than 3. More than that can break on mobile screens and make each column too narrow to read.
Images and file size: Follow the per-image recommendations in the sections below, and keep each individual image up to 350 KB.
For general best practices on email signature dimensions across all email clients (not specific to WiseStamp), see our guide: Correct Email Signature Dimensions.
Recommended image specifications for WiseStamp signatures
Use these recommendations as a starting point for any image you upload to a WiseStamp signature.
Dimensions: 200×200px
File size: Up to 350 KB
Resolution: 72 DPI
Format: .png, .jpg, or .gif for animated images
To keep your images sharp on high-resolution displays, upload an image about 2x as large as you want it to appear in your WiseStamp signature.
Image size is ultimately a design choice — most company logos in WiseStamp signatures are somewhere between 60–100px. However, feel free to adjust the size to fit your overall signature design.
Recommended dimensions by image type
As a more specific starting point, these are common display dimensions for each type of image. Treat them as flexible guidance, not strict rules, and remember to upload at roughly 2x the display size for sharpness:
Horizontal logo: 150–200px wide and 70–100px high.
Vertical logo: the same proportions in reverse, 70–100px wide and 150–200px high.
Square or circular logo: 150–200px on each side.
Profile photo: 80–100px square.
Promotional banner: around 100–200px high (see the banner section below for width, which is capped at 500px in the Studio).
Most mobile email clients render at roughly 400px wide, so a logo wider than about 200px can push your contact details below the fold on smaller screens.
Choosing the right file format
The format you choose affects how your image renders across email clients:
.png is best for logos and icons because it supports a transparent background. A transparent background prevents a white box from appearing around your logo, including on colored backgrounds and in dark mode.
.jpg works well for photos, such as profile photos, where a transparent background is not needed.
.gif is the only format that supports animation (see Using animated GIFs below).
If your logo exists as a vector file (such as SVG, EPS, or AI), start from that file when you create the image, since vector files can be exported to a sharp .png at any size without losing quality.
Why you should upload images at 2x the display size in WiseStamp
Most images in a WiseStamp signature display at around 100px wide. We recommend uploading your image to WiseStamp at roughly double that size — about 200px — for two reasons:
Sharpness on high-resolution screens. Higher-resolution images look better on Retina and other high-resolution screens when your WiseStamp signature is viewed.
Protection against email clients that ignore set dimensions. Some email clients display an image at its original size instead of the size defined in your WiseStamp signature. Uploading a larger image helps it still look correct when this happens.
Because some email clients (including certain Outlook versions) ignore the display size set in the signature and show the image at its original file size, it is best to resize the image file itself to the size you want before uploading, rather than relying only on resizing within the WiseStamp editor.
Resolution: why 72 DPI is enough
Set your images to 72 DPI. Email clients display images at screen resolution, so a higher DPI does not make the image look any sharper in an email; it only adds file weight. Sharpness on high-resolution screens comes from uploading at roughly 2x the display size (as described above), not from a higher DPI.
Balancing quality and file size in your WiseStamp signature
Higher-quality images look better on high-resolution screens, but they also increase the overall size of any email that carries your WiseStamp signature. The right choice depends on your priorities: a higher-quality image gives a sharper result with a heavier email, while a smaller file keeps the email lighter with slightly less detail.
Adding a banner to your WiseStamp signature
Promotional banners are wider than logos or headshots, so they use different starting dimensions when you add them to your WiseStamp signature. Use these recommendations as a starting point:
Width: In the Studio, the signature and banner width is capped at 500px. If you enter a value larger than 500px, the Studio reverts it back to 500px, so design your banner to fit within 500px wide. This limit keeps your signature rendering correctly across different email clients and devices, since wider signatures can appear inconsistent or get cut off for some recipients.
Height: The Studio does not have a separate height input for banners. A banner's height comes from the proportions of the image file you upload. To change the height, resize or crop the banner image to the proportions you want before uploading it, then upload the adjusted file. A common banner height is around 100–200px.
Format: .png for banners that include a logo or text, or .jpg for photo-based banners.
As with other images, upload your banner to WiseStamp at roughly 2x its display size to keep it sharp on high-resolution screens, while staying within the 500px width.
If you need a banner wider than 500px, the Classic Editor allows more width. Please note that the Classic Editor is scheduled to be deprecated on August 15, so we recommend designing your banner to fit within the Studio's 500px width whenever possible.
How dark mode affects signature images
Some email clients display messages in dark mode, which can change how your signature images look. Images that have a solid white background can show a dark box around them, or in some cases appear to disappear against the dark background.
To avoid this, use .png images with a transparent background for logos and icons. Transparent PNGs render correctly in dark mode across Gmail, Apple Mail, and Outlook.
Using animated GIFs in your signature
GIF is the only image format that supports animation in an email signature. Keep these points in mind:
Animated GIFs display in Gmail, Apple Mail, and most mobile email clients.
Outlook for Windows does not play animation and shows only the static first frame, so make sure that first frame looks good on its own.
Keep animated GIF files as light as possible to avoid slow loading and deliverability issues.
Notes and limitations when adding images in WiseStamp
Keep these points in mind when adding images to your WiseStamp signature:
Images in WiseStamp signatures are not responsive on mobile devices.
Background images and overlapping images are not supported in WiseStamp signatures.
WiseStamp hosts your signature images on its servers and references them by link, rather than embedding them in each email. Externally hosted images load more reliably than embedded ones.
Embedded images keep your images visible in clients like Outlook, but they increase the overall email size.
Images may not display in forwarded emails for every recipient. Some email clients strip images from forwarded threads. This is an email client limitation, not an image sizing issue.