Manual:$wgMaxImageArea/de

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.

If set to, MediaWiki will not check the size of the image before attempting to scale it. Extensions may still override this setting by using the hook.

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 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.

Beispielcode
You have to add any of those lines of code is to be added at the end of the LocalSettings.php file found on the root of your wiki directory:

Für 25 Millionen Pixel oder 5000×5000: Für 36 Millionen Pixel oder 6000×6000: Für 49 Millionen Pixel oder 7000×7000: Für 64 Millionen Pixel oder 8000×8000: For 81 million pixels or 9000×9000: Für 100 Millionen Pixel oder 10000×10000: