Size restrictions on images

This page provides additional information for the maxWidth, openFullMax and openMaxWidth properties of Asset.

Scenarios

1. No roles, maxWidth=0, openFullMax=0, openMaxWidth=0

Anyone can request any region up the the Platform imposed limit (e.g., 10000). This includes upscaling.

This platform maxWidth is added to the info.json automatically.

Thumbnails are created according to the thumbnail policy, with only the image size itself acting as a limit (or system maxWidth if it hits it).

2. No roles, maxWidth=1000, openFullMax=0, openMaxWidth=0

Conforms to IIIF Image API behaviour for maxWidth. The size parameter of any request cannot exceed an image that would exceed a maxWidth bounding square. When size parameter is max the resulting image is confined to the maxWidth bounding box.

Thumbnails are created according to the thumbnail policy up to the bounding square defined by maxWidth.

3. No roles, openFullMax or openMaxWidth != 0

openFullMax or openMaxWidth are ignored and the behaviour is the same as for maxWidth above.

4. Has roles, maxWidth=0, openFullMax=0, openMaxWidth=0

The image service has a probe and related IIIF Auth services. Only users with one or more of the image's roles can see any pixels.

An authorised user with a role can make size requests up to the platform limit.

No thumbnails are produced, whatever the policy.

5. Has roles, maxWidth=1000, openFullMax=0, openMaxWidth=0

The image service has a probe and related IIIF Auth services. Only users with one or more of the image's roles can see any pixels.

An authorised user with a role can make size requests up to the maxWidth limit.

No thumbnails are produced, whatever the policy.

6. Has roles, maxWidth=0, openFullMax=400, openMaxWidth=0

The image service has a probe and related IIIF Auth services.

Any user, including anonymous, can see /full/ requests that fit a bounding square defined by openFullMax. Only users with one or more of the image's roles can see non-full regions or sizes larger than openFullMax.

An authorised user with a role can make size requests up to the platform limit.

Thumbnails are created according to the thumbnail policy up to the bounding square defined by openFullMax.

7. Has roles, maxWidth=1000, openFullMax=400, openMaxWidth=0

The image service has a probe and related IIIF Auth services.

Any user, including anonymous, can see /full/ requests that fit a bounding square defined by openFullMax. Only users with one or more of the image's roles can see non-full regions or sizes larger than openFullMax.

An authorised user with a role can make size requests up to the maxWidth limit.

Thumbnails are created according to the thumbnail policy up to the bounding square defined by openFullMax, or maxWidth in the unlikely event that it is lower.

8. Has roles, maxWidth=0, openFullMax=0, openMaxWidth=512

9. Has roles, maxWidth=1000, openFullMax=0, openMaxWidth=512

10. Has roles, maxWidth=0, openFullMax=400, openMaxWidth=512

11. Has roles, maxWidth=2000, openFullMax=400, openMaxWidth=512

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touched 2025-09-23T12:04:54