Based on the comments to OP, you need to change the way you run the query if you want this to work. Below is how I would’ve done it.
$update = "UPDATE mod_document_images SET image_os_res="" . $checkbox_os . "", image_ne_aut="" . $checkbox_ne . "", image_ge_cat="" . $image_gen_cat . "" WHERE image_id = " . $image_id;
echo "Query: " . $query; // Echo the query containing the variables supplied
$result = mysql_query($update); // Run the update and store the result in $result
solved Print out UPDATE and DELETE query [closed]