I used a plugin for upload images, that also have one line code just put into theme page (s) and image gallery/ sliding images display, but I don't like there display style and format, so I used my own display format. Its working fine, but just a expert or using your experience give me advice or suggestions it is correct or not (see the below code). And one think, is it any issues about the performance or website security?
<?php $sql=mysql_query("select * from table_name");
Here my own display format like <div>, class, font etc.
<?php } ?>