Running TYPO3 on a Windows server and getting strange warnings in install tool about the size of the generated GIFs?
It happens in Install Tool -> Image Processing -> Writing GIF and PNG and the warning messages look like this:
File size is very different from reference in Section "Write GIF" (21 K instead of 14.4 K of reference image)
I experienced this on several Windows systems using different versions of PHP5. By chance I found that this correlates with the usage of GDlib2. By deactivating GDlib2 the created file has the same size as the reference image and the warnings disappear.
To deactivate GDlib2 use…
$TYPO3_CONF_VARS['GFX']['gdlib_2'] = '0';
…in localconf.php. Actually the default setting is to deactivate GDlib2, so you probably only have to eliminate any line that sets the above parameter to 1.
Another possible reason…
… for the image size warnings is a change of the JPEG rendering quality setting in TYPO3. Some setting like this will definitely give you warnings in the image read (!) tests:
$TYPO3_CONF_VARS['GFX']['jpg_quality'] = '95';
And this affects all image file formats in the install tool tests! So JPG, GIF, PNG, TIF, BMP, PCX, TGA… they all produce a size warning message in the install tool image read test.