Problem in uploading files

Hi all
I am unable attach pics in the thread. I have attached many times previously. But now, an error is occurring saying the file size is large. I tried cropping it, but it is not working. How to decrease the size of file? Or any other option to upload a pic?
Could anyone please help me with it?
Thanks

 

Open image with paint, then save it as jpeg. ( provided u r using laptop to access )

 

Thank you deepak.