Sorry for the necro-post, but I think I've found the problem. It looks like there is an off-by-one error in the IPTC block being written. For the image posted above, the length of the IPTC block is given as 20 bytes, but the lengths of the individual data elements in the IPTC block are 2 and 7 each. Add in 5 bytes each for the marker(2) + type + size(2) and that's a total of 19 bytes. The last, extra byte seems to be a 0. Perhaps the data being written is accidentally adding a NULL terminator?

I think this is a required "padding" to make Adobe applications happy. The IPTC record must have a length dividable by 2, and hence a padding zero byte is added.

As said, my tests show that Picasa handles UTF-8 encoded IPTC (with the same padding) correctly. After checking that I have given up on Picasa. It is not used in professional environments much, and that's my main focus for IPTC.

You're right. Adobe does indicate the padding should exist. Some applications correctly add the padding while others seem to just ignore it.

Anyways, this is indeed a problem with Picasa. Sorry for the troubles!

It's even worse. Some Adobe applications just refuse reading a file with "unpadded" IPTC data, others lamely complain about "unknown meta data" etc. It's always hard to find out in such cases what makes Photoshop unhappy, but a missing padding is sometimes the reason.

Older Nikon Capture versions even required IPTC data to be aligned on four byte boundaries...

I doubt that the Picasa programmers take care to analyze such things. I doubt that many Picasa users even know about Photoshop, Capture or other applications you find in "professional" workflows. Picasa is not intended for such small markets. It's just another Google vehicle to sell more ads.

Hello
Have the same problem with Picasa3 Beta, no tags. Played around a little bit with XNView Shell (which I know longer than IMatch and are more familiar with).
- If, in the Explorer context menu, I write the ITPC data (changing nothing else) using XNView Shell without changing date/time (checking the box) -> Picasa does nothing
- If I still don't change anything, but let the box unchecked (changes the modified date) -> Picasa does an update and the tags appear
- I tried the same with the ITPC edit in IMatch (force update), but didn't get the same result (but I am new to IMatch so I may have overlooked something) and this doesn't change the modified date
- If I go to Picasa and there on properties, it shows the keywords in this window (all of them, even the ones it doesn't want to show in the thumbnail view), sometimes (magic ?) after clicking this window it decides to update (i.e. there is the small thumbnail in the right hand corner and the tags are there
- Refreshing the thumbnail doesn't help and I haven't found any update database in Picasa.
I will write this to Google too, just thought you might be interested. I forced Picasa3 to update by removing and readding the folders with the test photos to Picasa3, the tags appeared as written by IMatch. Changing the IPTC data in IMatch does not change the modified date -> Picasa doesn't update -> tags do not appear. Forcing an update -> tags are there. I had the original problem because I read in the images in Picasa2 already, before tagging them in IMatch and then installing Picasa3. This is definitely an update problem (and not on your part but on Googles part). But just from curiosity, is there a possibility to change the modified date with the ITPC editor ? Or any other possibility I am not aware of ? I still use the evaluation version (that's how new I am to IMatch ;-)), so I cannot save in edit mode.
Sorry for the lengthy post, but I think this information may help someone, who has the same problem.

Make sure you have not set the option to keep the file date/time when modifying IPTC data in IMatch. Go to Options > Preferences > File Format Preferences and make sure the setting is Off.


Please be extra careful when you modify your meta data with Picasa, especially if you intent to you your IPTC later with some standard processing systems as utilized by certain web sites, stock photo agencies etc. They are usually very picky about IPTC data, and how it is written...test throughout to ensure that the IPTC data conforms to the IPTC standard.