If you’re looking for a ‘simple’ method that works on PC, tablet and mobile then try this.
Go to https://postimages.org/ and leave it as the default 'do not resize my image' in the first box (though you can select something else if you want it bigger/smaller).
Leave the default ‘no expiration' in the second box.
Click on the 'Choose Image' button to select your image to upload and let the website upload the image.
Once it is uploaded click on the small icon to the right of the ‘hotlink for forums’ row and it will copy the relevant link. Occasionally, clicking on the Hotlink for Forums doesn't work, if that happens simply go to the adjacent box and select the text for the link and then copy and paste it.
I use Imgur and find it easy. New post, Choose photo or video, then your computer titels appear. double click on the photo you want and it appears on Imgur. Go to top right of photo and three dots appear with copy link. Copy the one for forums and just paste it onto the post section.