Make icon size consistent

[matthijsmelissen]

Add the moment, we are using a mixture of 16px, 20px, and even 24px icons, without clear reasoning why some icons are bigger than others.

Would using the 16px versions for all icons be an improvement?

Here an overview of all icons in different sizes can be found: http://www.sjjb.co.uk/mapicons/contactsheet

[mboeringa]

The 16px seems reasonable: as small as possible to save space, but still readable. The 12px definitely will be to small for on-screen display like on the main OSM website I think, and for the elderly with less than optimal eye-sight.

Maybe a couple of icons could be chosen bigger though, like the B&B. I wouldn't necessarily stay to strictly at the 16px for all icons if they are not so clear at 16px.

[pnorman]

The icons which are 16px may also have transparent pixels around the edges, so a simple image size is hard to give.

[matthijsmelissen]

See also #630.

[kocio-pl]

We now have a 14px as a standard, I guess this issue can be closed now.

[matthijsmelissen]

It seems like we still have a couple of 'old' icons with different sizes, like for golf and slipway.

Also, it seems some of the icons are 14px, and others are 16px including a white border. It would be nice if we could unify that too.

[kocio-pl]

Now I doubt if that's possible - like I said in #1145 (comment), we have some 20 px icons (slipway - probably it's hard to make it smaller without compromising readability) and some 10 px (waste basket - by design).

I can live with that and I think it's enough to have a common size mentioned in our icon guidelines.