Hardening fcl-Image breaks loading imagelists in Lazarus

If I open existing (Delphi original) forms with timagelists this breaks hopelessly with trunk, and sometimes even crashes lazarus causing it to enter an endless loop between switching between .pas and .dfm

The last time I built this application succesfully was mid december.

To test I reverted to trunk revision 0681d239 of 13 jan before the "hardening" changes to fcl-image and it started working again. (same lazarus source)

Though in theory it could also the inlining problems, I suspect the image changes. I tried to find this difference out myself, but I'm not really experienced debugging Lazarus itself, so I failed.

Note that the attached project doesn't necessarily compile. It is about opening actiegrid in lazarus and making the form appear in the designer mode. If it fails (probably due to an exception in fcl-image code) it opens in dfm text view.

It might be related to slightly different bmp formats as used for .ico? Are timagelist pictures ico's ?

imglisttest.zipsion failed.