# Extensible File Thumbnails
## Introduction
When sending media, it is often helpful for users when a thumbnail can be shown before the
actual file is finished downloading.
XMPP already has a protocol for specifying thumbails, [Jingle Content Thumbnails](https://xmpp.org/extensions/xep-0264.html).
However, this protocol requires that the thumbnail is a base64-encoded image published using
[Bits of Binary](https://xmpp.org/extensions/xep-0231.html). This prevents clients from implementing newer technologies, such as
[Blurhash](https://github.com/woltapp/blurhash).
This document specifies are more general and extensible element for specifiying thumbnails in various formats.
## Usage
```xml
LEHV6nWB2yk8pyoJadR*.7kCMdnj
```
In this example, the thumbnail contains only a blurhash thumbnail, indicated by the `` element, but an implementation
may add more versions of the same thumbnail, i.e. another `` element as a fallback if a client does not support
blurhash. To prevent confusion in the display of a thumbnail, all children of `` must describe a thumbnail
for the same file.
### Thumbnail Types
#### Blurhash
If a sender includes a `` inside the `` element, then it must be interpreted as
[Blurhash](https://github.com/woltapp/blurhash) data. As a sender, care must be taken to not make the Blurhash
thumbnail too big as to not loose the advantages of blurhash.
```xml
LEHV6nWB2yk8pyoJadR*.7kCMdnj
```
#### Jingle Content Thumbnail Compatability
In order to enable a pseudo-interoperability with [Jingle Content Thumbnails](https://xmpp.org/extensions/xep-0264.html), inclusion of a
`` element is allowed. This is to allow easy reuse of an already existent [Jingle Content Thumbnails](https://xmpp.org/extensions/xep-0264.html)
implementation.
```xml
```
## Usage Example with Stateless Inline Media Sharing
NOTE: This example is taken from [Stateless Inline Media Sharing](https://xmpp.org/extensions/xep-0385.html) and modified for this protocol.
```xml
Look at the nice view from the summit.
image/jpeg
summit.jpg
3032449
2XarmwTlNxDAMkvymloX3S5+VbylNrJt/l5QyPa+YoU=
2AfMGH8O7UNPTvUVAM9aK13mpCY=
Photo from the summit.
LEHV6nWB2yk8pyoJadR*.7kCMdnj
```
## Security Considerations
The same considerations apply as specified by [Jingle Content Thumbnails](https://xmpp.org/extensions/xep-0264.html).
## Todo
- Change XML namespace from `proto:urn:xmpp:eft:0` to `urn:xmpp:eft:0` once we submit this as an XEP
## Changelog
### 0.1.0
- Remove the base64 thumbnail type
- Namespace all thumbnail types
- Remove the type attribute of ``
- Rename `` to ``
- Rename the namespace from file-thumbnails to eft
- Rename from File Thumbnails to Extensible File Thumbnails
## Info
| Key | Value |
| --- | --- |
| Author | PapaTutuWawa |
| Version | 0.1.0 |
| Short name | eft |