Upload and insert banners and logos
SignatureCat keeps two kinds of company images in a per-workspace library: logos (115x115 px by default) and banners (450x100 px by default, scaled down on small screens). Each template selects its own logo and banner, inserted with the {{logo}} and {{banner}} tokens - and can resize either one for itself with the visual editor's resize handles.
Add an image to the library
- Open a template in the editor on Signatures.
- Click Logo or Banner in the toolbar - each opens its own gallery (logos and banners never mix).
- Choose Add to library, then either:
- I have a link - paste a public HTTPS URL of an image you already host, or
- Upload a file - PNG, JPG or GIF, recommended up to 200 KB (hard limit: 5 MB, animated GIF up to 20 MB).
- Optionally set a library label, a click-through link ("On click, leads to") and an Image description (ALT), then save. The image is added to the library and selected for this template.
For banners you can also give the library entry its own size (a checkbox with width and height fields, 24-600 x 24-400 px) - both when adding the entry and later in the selected entry's details. That size becomes the entry's default wherever it is used; clearing it returns to 450x100.
Insert into a template
Pick an image in the gallery and click Use selected - the editor can also insert the {{logo}} or {{banner}} token at the cursor for you. At render time the token becomes a proper image tag; if the image has a click-through link, it is wrapped in a link automatically.
If a template uses {{banner}} without a selected banner, a neutral placeholder renders instead and the editor nudges you to pick one - the signature never breaks.
Image sizes: library default vs per-template
Two layers control how big a logo or banner renders, and the more specific one wins:
- Per-template size - set with the resize handles in the visual editor (banner 24-600 x 24-400 px, logo 24-300 px). It applies to that template only, so resizing a banner in one template never changes the others sharing the same image.
- Library entry size (banners only) - the entry's own default described above.
With neither set, the defaults apply: logo 115x115, banner 450x100.
Click-through links
The click link travels with the library image, not the template: update the link once and every template using that image picks it up on the next render. This is handy for rotating campaign banners - swap the target URL without touching templates.
When one template should behave differently, select the image chip in the visual editor and use the Link button: keep the library link, remove the link for this template only, or point it at a different URL.
Image description (ALT)
Every library image can carry an Image description (ALT), up to 300 characters. The app puts it plainly: "The recipient will see this description if their mail program cannot display the image." Many people read mail with images blocked by default, and screen readers announce the description instead of the picture, so a logo entry described as "Acme logo" still says something useful.
Set it when you add the image (both I have a link and Upload a file), in the image step of the new-template wizard, or later in the Selected image details panel of the library. Like the click link, the description belongs to the library entry, so every template using that image ships the same one - and images you host yourself get the field just like uploads. Leave it empty and the image is rendered as decorative, with no description.
Sizing recommendations
| Kind | Default rendered size | Recommendation |
|---|---|---|
| Logo | 115x115 px (resizable per template up to 300 px) | Square image, PNG with transparency works best. |
| Banner | 450x100 px (custom sizes up to 600x400 px; max-width 100%) | Export at twice the display size for sharp HiDPI rendering, keep the file under 200 KB. |
Large images slow down email rendering and can push messages into the "message clipped" territory in Gmail - keep files small.
Deleting images
Deleting a library image detaches it from every template that selected it - those templates fall back to the placeholder and keep applying normally. The app warns you first: "This image is used in N template(s). After deleting it will no longer show there - a placeholder appears instead."
If the deleted image was still in use, SignatureCat also tells the workspace: an in-app notification ("A logo used by your signatures was deleted") appears in the bell and an email goes to the admins and the owner, listing the affected templates. Nobody has to spot the placeholder by accident.
Images you added with I have a link are not affected in that way - the file stays on your own server, so old emails keep loading it. To swap a hosted image safely, upload the new one, point the templates at it, and delete the old entry only once you are sure nothing needs it.
Where images are served from
Library images are hosted at images.signature.cat by default. To serve them from your own subdomain (better deliverability), see Serve images from your own domain. External URL images ("I have a link") are always fetched from wherever you host them - they must stay publicly reachable over HTTPS.