When attaching a 'tif' file to a posting, the error 'Error parsing server response' is received. I have replicated this error with a tif file that is 319KB in size.

Using the browser development tool's network page, here is the reported error:

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[phpBB Debug] PHP Warning: in file [ROOT]/vendor/marc1706/fast-image-size/lib/Type/TypeTif.php on line 80: unpack(): Type v: not enough input, need 2, have 0
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Refer to phpBB support forum topic:

https://www.phpbb.com/community/viewtopic.php?f=556&t=2499041