Hey i am trying to upload an image i want as my forum picture. I am uploading it from imgur but when i do it just shows invalid URL and i am not able to upload the same. please can u tell me is there any other way to upload the picture.

Are you sure you're taking the direct URL of the image? It should end in .jpg .png .gif or some be other image format.

Follow the steps given below

Select the image's URL , go to tinypic.com , there u will see 3 options image , video & URL ,select URL , put the URL link u copied then , below it change default to avatar , then upload ur pic , then copy the newly uploaded pic's URL & paste it on the forum where it is required
Still if u face difficultly check out some old threads , ilona made a step by step guide for this including pictures