Vinyl Scratch.

@Vinyl Scratch. I use 1000x165 for my profile banners and that seems to work well. 

Generally there are no ideal dimensions, but few years ago I made a template that more or less shows what to expect.

1310 is the max width and banners never take more than this to be displayed, so going past that point is a waste of filesize you could use for height instead. Using smaller (like 1000px width) is fine if you need to reduce filesize - the banner will be upscaled to fill horizontal space.

With height though, it's all over the place. 1310x350 is, or at least used to be, the size of banner when viewed on PC with full site size. On mobiles though, banners are more square-y, so more can be seen and it varies from phone to phone.

The general strategy is to have as tall banner as possible (keep in mind filesize limit), and keep the most important things at the top. 1310px would be ideal width, lower will cause quality drops when viewed on PC. The lower the width, the more blurry the image can become.

It's been a while though, so things may have changed a bit. I'll have to look at it later and perhaps make a new template.

@Sparklefan1234 I guess it depends on what you're aiming for, because on mobile it looks more like a signature, with tons of unused space above it.