Limit memory usage
The initial memory usage is under 40MiB, but after searching for some radios, it goes up to 170MiB...
It think the problem resides in the image cache. Probably limiting the cache to X images, and making sure they have a maximum size, would greatly reduce the memory usage.
You could also add a timer: after 5 mins an image isn't used, just remove it from the cache. The cache is needed the most when looking for new stations. It doesn't make sense to keep 500 images in cache after 10 mins of listening the same station.