I gather you have reached a solution based on the replies already posted, but just for the sake of TMTOWTDI, your data would make a nice case for customizing the INPUT_RECORD_SEPARATOR variable, $/, like so:

{ # customize $/, but only inside this code block:
    local $/ = "----------\n";
    while (<FILE>) {
        chomp;  # this removes $/ from the end
        my ( $image, @attributes ) = split /\n/;
        $image = s/^image:\s+(.*)/\L($1)/;

        next unless ( exists $db->{$image} );

        # do something with @attributes...
    }
}
# now $/ is back to normal
# (updated to add chomp call)
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Note that if you are using modules or reading from other files while doing things with the attributes within that block, the altered value of $/ will be in effect -- you may need to create more block boundaries to localize it again back to its original value.