Create picture gallery and fix another one so it appears on mobile

First assignment, Create a picture gallery on this website [login to view URL] Functionality has to be like this: [login to view URL] [login to view URL] it must be very easy to add and remove pictures. it must automaticaly create individual alt tekst for every individual image,for a good google optimalisation, which we can adjust easily. It must be responsive for on moblle phones, tablet and pc, and suitable for all browsers. Second assignment: Fix this picture gallery on the entire website: [login to view URL] It is good on the website, but not on mobile phones. The images overlap, and the need to have the same proportion, this is a problem for the entire website. for example: [login to view URL] if you look on a mobile phone you see the images of all galleries overlap, they have to be in the same proportion, only on a mobile in one line down. There is also a problem on the home page, if you look at a mobilephone, one image is bigger and not in one line with other images. If there is created a new gallery, this automaticaly needs to be fixed, so not solving the problem for now, but solving it for every gallery which will be created.