FTP and inserting new images into Style Sheet

[SOCHICM]

Hello!

Ok so I have already set up Filezilla with my hosting account. Now I have uploaded a few test images and put them into the child theme directory images folder like I have read on other threads. However if I am looking to change the url of an image in the style sheet ex: url (images/icon-bookmark.png) with a custom image I created, do I use the same url format ex: url (images/newicon-bookmark.png)?

I have tried this and it doesnt change the original image that came with the template (BeeCrafty). Does the url need to be worded differently like <img src= etc...? Do the images always need to be uploaded to this exact folder? Please help!

Thank you!