SUB Image — A .sub file is a SUB Image. It is a raster or vector image format used for photos, web assets and design work.
Quick facts
What is .sub
A .sub file is a SUB Image. It is a raster or vector image format used for photos, web assets and design work.
In the mime-db registry it maps to image/vnd.dvb.subtitle. When serving .sub over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to image/vnd.dvb.subtitle — and is delivered over HTTP via the Content-Type header.
How to open .sub files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: image/vnd.dvb.subtitle
Common software that reads/writes .sub:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .sub files
How to create .sub files
Frequently asked questions
Common options include Photoshop, GIMP, Paint. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .sub extension.
image/vnd.dvb.subtitle is the media type identifier used for .sub files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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