This is the same photo, taken using Camera+, uploaded multiple times.

1) Directly from iPhone using the WordPress app. Inserted as ‘large’, which is around 1024px per side. Clicking on the photo still does not show it full size.

2) This photo was exported from Aperture at 2048px each side, i.e. nearly the original iPhone resolution. I uploaded it via WordPress using the standard web interface, which didn’t offer different resolution options for upload. I then inserted it into the post as ‘large’ (i.e. 1024px per side). Despite this the image looks larger in the post, and if clicked will display at full resolution. Hmm.

3) Finally, the same photo uploaded from the iPhone WordPress app, but at ‘full size’ (about 2600px per side). It now behaves pretty much like the desktop version, at the cost of rather more data being used during the upload.

Moral of the story: The WordPress web interface does not ask for desired picture size; it uploads what it is given. Its question on display size refers to the size of the uploaded image to be displayed in the post. Clicking the image will show it at full resolution. The iPhone app also asks for the desired size to display the picture in the post, but compresses the image to be uploaded to that size prior to upload. Hence clicking the image will not make any difference. This is reasonable considering the WordPress app is likely used on the move with limited data allowance. Still, it’s worth keeping this in mind.