E-cards are electronic greetings usually sent by messages but more commonly by email. Below is a Christmas e-card I made.
E-cards are usually very beneficial over traditional paper cards because they can be sent electronically and to numerous people whereas with traditional paper cards they must be handmade, hand-written and sent out separately by post. E-cards also have the ability to be animated when viewed - this is the main benefit over physical cards. However e-cards are not always beneficial because in case of a slow internet connection the e-card might not load for the receiver, and if it does it could be very slow. The technology behind e-cards is the animation file formats - most commonly they are of the GIF format. When e-cards are sent by email they are usually attached as they are an image themselves. Attachments in emails are very simple - when composing the email the option to attach a file is available, and the user just needs to locate the file and then upload it, it is then attached and sent with the email. Sometimes e-cards have sounds that play along with it, and this increases the file size further for the better quality of presentation - it will play a sound for a better experience.
https://www.hallmarkecards.com/ is a well known professional e-card creator. They offer e-cards for numerous events.
Animations are used on various types of technology. This usually includes mobile phones, desktop computers, laptops, tablets, and public display screens (standalone screens in public places). These devices have different abilities. In terms of animation, mobile phones and tablets can load animations (modern smartphones have no problem) however it does put stress on the devices because they are obviously built with weaker CPUs/RAM and it also depends entirely on connection - mobile devices usually have lower connection speed than desktops/laptops especially being wireless and the wireless hardware is not as strong. This means several things for the developers. They would have to adjust it for screen sizes - while it can fill a mobile phone's screen, if viewed on a computer monitor it might be very small. Resolution also fits into this but with the added factor of higher resolution = higher file size/quality leading to loading times and connection problems upon loading it due to the added detail. Download speed is very vital too because longer loading times are usually a result of file sizes or bad internet connection. Colours in images also increase the file size. GIFs already are limited in colours but reducing the number of colours even further can help to reduce a heavy-load animation thus making it easier for tablets/mobile phones to view whereas desktop users won't find problems due to the good processors. Formatting can be a problem but a rare one as GIFs are very common on the internet right now. Mobile devices made by Apple don't have access to Flash which can sometimes cause a problem, but when animations are in GIF format they can be viewed easily. Considering how easy it is for an animation to be in GIF format this is not that big of an issue.

