Manual:$wgMaxImageArea

Details
This value specifies the maximum number of pixels a source image can have if it is to be scaled down by a scaler that requires the full source image to be decompressed and stored in decompressed form, before the thumbnail is generated.

This provides a limit on memory usage for the decompression side of the image scaler.

The limit is used when scaling images with any of the built-in image scalers, such as ImageMagick or GD.

It is ignored for JPEGs with ImageMagick, and also when using the vips>Special:MyLanguage/Extension:VipsScaler|VipsScaler extension as these situations do not cause excess memory usage.

Default is 50 MB if decompressed to RGBA form, which corresponds to 12.5 million pixels or 3500×3500.

This is a list of examples for alternate values that may be used to set this configuration parameter:
 * 25 million pixels or 5000×5000:
 * 36 million pixels or 6000×6000:
 * 49 million pixels or 7000×7000:
 * 64 million pixels or 8000×8000:
 * 72 million pixels or 9000×9000:
 * 100 million pixels or 10000×10000:

To be clear, this only prevents scaling of large images. Users are still allowed to upload large files.