I create image upload and watch galery feature and I store each user image like this:
When user upload new image I update images column and It became like user_id_img1,user_id_img2,user_id_img3.For Fast SQL purpose is it good idea?Or shoud I insert new rows for each image from user?
This is the very basic stuff of database design, like multiplication table in arithmetic.
A column in database should always contain single value.
For the purpose of storing multiple data you have rows in your database. Therefore, always add another row for the each image.