On some systems, there is a feature called Retina Display. This function is mainly for certain mac systems and found less frequent in windows and other systems at this current time.
Retina Displays is a high screen resolution of 4k or 5k, meaning a monitor resolution of 3840 x 2160 pixels for 4k and 5120 × 2880 for 5k.
Retina Images is an image that can be viewed with great quality in these resolutions. So when you have a retina image and you view it on a retina display the image will be scaled to its 4k or 5k resolution that it was downloaded at.
When using a retina image and not viewing from a retina display, the image will be scaled down to best suit the viewing resolution. The reason for this is so that the quality won't change due to the difference of quality in resolution, so scaling the image down to speed up load times won't affect the quality of the image.
In Maglr, when using a retina image, it will save the retina image and a scaled down version of this image for viewers not using a retina display when it comes to viewing on all monitors of resolution the images will not be affected in quality.
When resizing the content in Maglr, it will take the 4k or 5k image and then scale it down to what to the size that the creator has set it as, if viewing on a non-retina display then the image will be scaled down in resolution.
Maglr will automatically control and size and resolution of your images for best viewing.
Taking a lower resolution image and scaling it up to the retina resolution does not make the image retina, it just stretches the image to that resolution and ruins the quality of the image. The raw image must have been made in that resolution of the retina in order for it to be retina.
The image formats below are the best-used formats for different situations, but can all be used as retina images.
JPG/JPEG: Best format for photographs or images that are generally used as a background or reference image.
PNG: Best used when you have an image with a transparent background, could be an image of a character/animal/object with a transparent background, so only object/character/animal is shown.
SVG: Best format for vector mages. Vector meaning an image that is purely made up of shapes can be scaled up and down to any resolution without losing any quality.
GIF: Best format for when you want to make a short video using multiple image frames played one after the next. Frame after frame to form a motion such as videos.