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?

I need to have a custom setting which should be modifiable via a visualforce page but I'm not sure how to access and as well as modify it via the visualforce page - particularly I'm not sure what the syntax should look like. This custom setting should be static per each salesforce org.

The custom setting I have now looks similar to (it is Public and is a List):
ccc_SettingObject__c

where it's custom fields are (both are Text(20)):
ccc_Something_Id__c
ccc_Somethingelse_Id__c

I'm trying to make a visualforce page and it's respective class that lets me modify / view the current value set to both of the fields.
This custom setting should be a single instance per each salesforce org. So an admin should be able to modify this setting (through the visualforce page) as well as view it's current value.

I've looked at sample solutions (1 (https://www.salesforce.com/us/developer/docs/apexcode/Content/apex_methods_system_custom_settings.htm), 2 (https://www.salesforce.com/us/developer/docs/pages/Content/pages_input_field_labels.htm), 3 (http://www.salesforce.com/us/developer/docs/pages/Content/pages_dynamic_vf_sample_standard.htm)) to this but am still uncertain of the syntax.

Summary:
Trying to make a visualforce page that displays (in a textbox) the current custom setting's fields which can be altered (after pressing a save button).

Is it possible to have a global variable in apex classes that is set (once) by the user via an apex page (form) within Salesforce?

The next time the user logs in or a different user logs into the same salesforce org the global variable would ideally be already set.

I need my managed package to ask the user to input a given guid so that the package can access this in the apex classes when calling out.

Currently I have a working package that calls out successfully to a web service, but the guid is hardcoded into the apex class (therefore it is static to all users).

What I want more specifically:
- The user installs a package.
- The package asks the user (via a tab? or a force.com page?) to input the guid the user would have been given before installation (elsewhere)
- The package calls out this input to the web service

This is done only once. The package acts by itself from then on - doing other things.

What is the best approach for this?
Force.com pages?
Tabs?
I'd likely need to create a specific object in Salesforce for this as well, but is it possible to only ever have a single instance of that object?

I've created a bunch of apex classes and triggers and placed them into a package which was then uploaded (via Salesforce -> Create -> Packages).

It produced a url for the package.

I've logged onto another Salesforce account and installed this package - and it seems what it did was just unpackage all the classes/triggers -- the functionality was working fine, but I could view all the code..

Is this all the package feature does? Provides a convenient way to pass classes from one place to another? Is there a way to conceal the classes from the user?

If I was to deploy this package to AppExchange, would people be able to view the code upon installing the app?

Or are the classes/triggers only viewable in developer accounts?

I have created apex classes and triggers on my developer account.

How can I make these become part of an app that can be deployed to the AppExchange?

That is, how can I share these apex classes/triggers with other salesforce users (accounts)? - besides literally copying the code without any confidentiality.

Are Salesforce apps made using external IDEs? (e.g. .Net development would be using the DeveloperForce.Force nuget package)