How can I stop character from walking through the ground

My character keeps walking through the ground. I'm not sure what the problem is. I feel I have had this issue before and solved the problem by changing the pivot point. Could someone please take a look at my capx and see if you recognize an issue.

Thanks

Fix your image collision and make it like this:

Thanks, I will give it a try now

Thanks again A0Nasser, it worked. I honestly have never had to use collision before so you also taught me something today.

You are welcome, don't forget to take a look at the tutorials section, this will save you alot of time.