Download and displaying image in a List is a bit complicated matter. Some points that you need to consider are:
- Using different thread to doing the image download, you can use android asynctask class for this, you read about it here
- Caching your image, there are several way to achieve this, caching in memory, internal cache storage, or external cache storage(SD Card), and please read here
- You can use Lazy Loading on displaying the Images, it's mean the apps doesn't download all the images together in the same time, instead it downloads them one by one using queue, since user may not want to see all the result all together, you will waste network and battery resource, for this topic please read here
I think it's better you learn about these, since they are very important. Hope it helps.