Image Memory Size limitation at Upload time on Oracle Apex 5

To make a limitation on uploading image on Oracle Apex 5. You can do this steps.
Step-1
Select the File Browser field and Create a Validation
Step-2
Then  Validation>> Type >> PL/SQL Function (Return Error Type)
and pest the code:

 declare
 cursor c is 
 select doc_size
 from apex_application_files
 where name = :P18_IMAGE; -- where write the name of file upload field
 v_size number := 0;
 v_msg varchar2(100);
begin

open c; 
fetch c into v_size; 
close c;
  
if (v_size < 51200) then -- (50 kb*1024 byte=51200)
  v_msg  := 'Image must be at least 50KB!';
  DELETE from APEX_APPLICATION_FILES WHERE name = :P18_IMAGE;  ---where write the name of file upload field
  return v_msg;
elsif (v_size > 204800) then -- (200 kb*1024 byte=51200)
  v_msg  := 'Image size cannot be more than 200kb!';
  DELETE from APEX_APPLICATION_FILES WHERE name = :P18_IMAGE;
-- where write the name of file upload field
  return v_msg;
end if;

--:p15_rcremark := :P15_RCAPPIMG_temp;
end;

Then save the page and try.