I'm trying to upload a logo.png (1kb) file to replace the default logo for an app in Salesforce.

I've been following many examples on the internet (1 (http://clicksandcode.blogspot.com.au/2011/12/how-to-add-your-company-logo-in.html), 2 (https://success.salesforce.com/answers?id=90630000000gpwGAAQ), 3 (http://forcemonkey.blogspot.com.au/2010/01/how-do-i-add-my-own-custom-logo-to.html)) but they all appear to be based on older versions of Salesforce - apparently the interface changed quite a lot since then and I see no links referred to in those examples.

How do I upload an image to Salesforce (v31.0)?

I've went to Setup -> Build -> Develop -> Static Resources and uploaded my image (set to Public) there but it doesn't appear when I try to use it to replace the logo of my app in
Setup -> Build -> Create -> Apps -> [my app] -> Edit -> Insert an Image

A popup shows up with 'My Personal Documents' and it shows there are no files there.

Where/How should I upload the image so that it is used with my deployed managed package?