Exemplary embodiments relate to techniques for improving the speed and rendering quality of an image (e.g., a JPEG), particularly in an end-to-end encrypted environment. The image may be analyzed on the sending-client side and the image data may be broken into a thumbnail and a full-quality image, where the full-quality image data relies on the thumbnail data to render a high-quality image. The image is uploaded to a blob store, and a message is sent to the receiving client with image information. At the recipient side, the JPEG image data is retrieved from the blob store and the thumbnail is first rendered. Subsequently, as the remainder of the image data is received at the receiving client, the image is updated. Consequently, images are rendered faster, and the thumbnail can be automatically downloaded so that a user can determine if they wish to download the full image.