# Viewing thumbnails of the source video
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AWS Elemental MediaConnect can generate JPEG-format thumbnails of the video that is in the source in any type of flow except for CDI flows. The thumbnail provides a visual verification that the content contains video. You can view the thumbnails on the console or retrieve them programmatically.

## How thumbnails are generated
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When you have enabled thumbnails in a flow and when the flow is active, MediaConnect generates a JPEG thumbnail with a 480 x 270 resolution. 

The rate for generating the thumbnail is as follows:
+ The fastest possible rate is one image every second.
+ The rate might be slower, depending on the characteristics of the source video. For example, one image every 6 seconds. 

## How thumbnails are displayed
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As soon as the thumbnail is generated, MediaConnect displays it in the flow **Details** page, in the **Preview** section.

It also makes the thumbnail available as base 64 binary data. You can use an AWS API to work with the binary data programmatically. MediaConnect encrypts thumbnails during retrieval to the console Preview window or in transit for API responses.

The retrieval rate for thumbnails is as follows:
+ The refresh rate for the MediaConnect console is every 2 seconds. If the rate is faster than the generation rate, the same thumbnail is displayed more than once on the console.
+ The API retrieve rate is constrained by the [maximum TPS](quotas.md#limits-api). This constraint only matters if you are trying to retrieve thumbnails for multiple flows.

  If you are retrieving thumbnails for only one flow, there is no point retrieving the thumbnail more often than every second (the fastest possible generation rate).

**Topics**
+ [How thumbnails are generated](#thumbnails-how-generated)
+ [How thumbnails are displayed](#thumbnails-how-displayed)
+ [Requirements for thumbnails](thumbnails-specifications.md)
+ [Limit on thumbnails in MediaConnect](#thumbnails-api-limits)
+ [Enabling and viewing thumbnails in the console](thumbnails-enable-view-console.md)
+ [Enabling and retrieving thumbnails programmatically](thumbnails-enable-retrieve-programatically.md)

## Limit on thumbnails in MediaConnect
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There is a limit to the number of thumbnails that you can view or retrieve. This limit is the TPS (transactions per second). The thumbnails feature shares the global limits for MediaConnect. For more details, see [Limits for API requests](quotas.md#limits-api).