You can't change the default browser as it has been built in with the assumption people wouldn't be spending time on making alternative browsers (that are based on IE anyway) in the market place. The closest you can come to this is to developer unlock your phone and find something that is similar to this application, but I doubt if that exists...
OK, so for the edit: This is dependent on your few things:
active/accessible internet connection
zune music pass must offer music from this artist in order to have some pictures of it/him/her
artist must be accessible for your country (yes again the same problem) - not all artist are accessible in all countries... :(
But there may be some other things that ...
If you have an Unlocked Windows Phone , I will strongly suggest you to try the Windows Phone Hacker Tweaks which brings in lot of customization including what you need.
Go to settings => Personalization => Lock screen (at the end of the page you will see double tap for wake up
Sorry because picture is on my language
Update: For L535 go to Settings => Extras => Touch, you will see first option for double tap for wake up
Unfortunately you can't.
This feature used to be in some of the preview builds but Microsoft pulled it out, citing issues with Start screen layouts. They said it would be quite some time before it was put back in, and given the current rate of development I wouldn't expect to see it any time soon, if ever.
For now, even on the latest release build (10.0.14393.693), it is not possible to have a large tile.
Try searching for such an feedback in the Feedback Hub about having a large tile option and upvote it your create our new one. Hopefully, this feature might roll out in the next OS updates, so be ready to install them.
Hope this helps. If it did, give me ...