How to judge whether the field access photo in the database is empty in Delphi

flower

For example, the type of access text can be judged as follows:
if query1.fieldByName('s_name').AsString ='' then

But when using BLOB type to access photos, how to judge whether this field (s_picture) is empty?

Thank you! !

theendfwc

query1.fieldByName('s_picture').IsNull

flower

Thanks!