Ensure image parent node exist, before select it.

[juliaroldi]

When select a position in Image selection plugin, check if the image parent node exist, so can it be selected.

[JiuqingSong]

actually position can never be null. The problem could be there is no parent element so that when we create Position, we stored null as node:

Then in createRange, when we get nodeType, it throws:

To avoid this, we need to check if there is parent node of image. If not, it is impossible to select the image so we just do nothing.