RAM - This is a memory chip that stores all your data and when you go back onto your computer it will have saved all your computer data and other things you have on it as well will be saved.
CPU - A CPU (Central Processing Unit) is the most important bit of the computer because it is where all the calculations happen, without the CPU it wouldn't be able to process the image and it wouldnt be able to make the image into a specfic size.
Storage - There are many ways you can store your photos, the most popular way is to have a file systme on your computer and you save them into a specific file. But sometimes this isnt reliable so you might have to save the photos or whatever your saving so you oculd save your things onto a CD or a USB stick . These are called back up storages so if anything happens to your orginal copy and it gets destroyed you then have it safe somewhere else.
Input devices - If you want to interact with your computer you can plug some things in it and they will allow you to interact with it, for example you can plug in a mouse and keyboard and you can type things in the computer and click on some stuff as well. You can also plug in a scanner and it will scan anything you want and put it on your screen so if you scan a drawing it will then show the drawing on your screen.
Graphic card - There are many different types of graphic cards you can get and they all are different from each other. You can get ones that are
Bitmap: Bitmap is made of small blocks that make the picture, they are different colors and they are all quite small, put together they all make a picture. If you use photoshop you will use bitmap images also power-point does as-well. Bitmap can be converted to any file (JPG,giff,png and bmp) and this is really convenient since if you have to save the image into a specific thing then you can. The advantages of using bitmap is that it can handle any colours and it makes it easy to make.
Vector: They use maths to decide the size the colour and shape. With vector if you make it small or big it wont change since it is done with maths, but if you try to downsize it in bitmap it will make it all blurry and hard to see
There are many differences between lossless and lossy compression techniques but i will go through the main difference . Lossy is where it destroys certain bit of information from the file to reduce it down. However though it can delete some important data from the file so they may not have the original dat in them when you open it next time. Lossy is normally used for videos and sound since it is easy to detect the important info and the less important. Lossless is where it compresses the data in the file but all the data is there so not one bit is missing but if i bit does goes missing it then instantly recovers it for you. It is normally used for a spreadsheet file or text file