I may be late to help you on how to post images and the bbcodes needed to post images is already provided and all you need to deposit is to copy the link of the image you uploaded. Just make it ends in image format like .jpeg, .png and other image format that bitcointalk supported. As of now, you are not eligible to post images due to your rank which is still a newbie. To be able to post images, you need a jr. member rank which requires 1 merit and 60 activity points just do a research on how to achieve that requirements and second is to buy copper membership which you don't need to rank up but have to pay btc. To upload images you can use imgur app or on site and other same apps or services that let you upload images that will be shared.