Alternative for NULL values of a block variable

Hi all,
can anyone tell me how it is possible to do something like the above.
This does not work :(.

Have you tried nodata? http://www.tinybutstrong.com/manual.php#html_block_prm_nodata

nodata is not what I want, this would work if the playerblock is empty. But that is not the case, its just the image_id might be null if not yet initialized.

Perhaps it would be easier to initialize the playersblock.image_id to 'images/default.png'?

I don't know about using field conditionals with blocks, but since you are reading a field from the block, maybe ifempty would work for you?

I solved the problem using '' instead of null, thx for the input, found that while looking for a ifempty solution :)