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![Waqas Khan](https://secure.gravatar.com/avatar/046a8214a31c2db963eddbcd52c3cea6?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Waqas Khan
Courses Plus Student 2,661 PointsWhy there are so many images format?
Why there are so many images format?
do I have to use all of these images format...
can we use GIF format?
3 Answers
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsSome image formats are more effective for certain kinds of material. Others may offer features that are only needed occasionally. For example, the GIF format you mentioned will store animation sequences and transparent areas, where JPG will not. But JPG is much more efficient when storing content with lots of colors such as a photograph.
And yes, GIF is a common image format supported by all browsers.
![David Williams](https://uploads.teamtreehouse.com/production/profile-photos/9702032/micro_DavidWilliams.jpg)
David Williams
180 PointsAs a Web developer, it is important to understand the differences between image formats. As Steven Parker already pointed out, different formats are used in different situations. The three most common image formats for the Web are JPG, GIF, and PNG.
As you improve your Web developer skills, you may want to take a little time and familiarize yourself with these formats. The University of Michigan has a nice introduction to images to get you started.
![web pad](https://uploads.teamtreehouse.com/production/profile-photos/9752462/micro_Green_tea_latte.jpg)
web pad
4,483 PointsThank you for the info and the link.
![web pad](https://uploads.teamtreehouse.com/production/profile-photos/9752462/micro_Green_tea_latte.jpg)
web pad
4,483 PointsI tried to upvote your answer, but it goes to -1. I don't understand how this up down arrows work. I thought if clicking the up pointing arrow it means you like the answer. How come i clicked it, it goes negative 1 instead (-1). Anyways, I am upvoting your answer still. Thank you for the answer
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsVoting box info:
Clicking the "up" chevron (arrow) over the vote box will raise the vote, and the down chevron will lower it.
If you up-voted before, the box will be green, and clicking "up" again will cancel your previous vote. If you down-voted before, the "down" chevron will be red and clicking it again will also cancel the vote. Clicking on the opposite chevron from a previous vote will both cancel the old vote and register the new one.
The person who asked the question also has the option of choosing a "best answer". This does not change the vote number, but gives the answer a green background. It also gives the question a green check-mark in the forum listing to let everyone know the issue has been solved. Only the original poster has this option.
![Waqas Khan](https://secure.gravatar.com/avatar/046a8214a31c2db963eddbcd52c3cea6?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Waqas Khan
Courses Plus Student 2,661 PointsThank you! One more Question?
do we need to adjust the pixel of the pictures every time?
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsI'm not sure what you mean by "adjust the pixel". Can you elaborate a bit?
![Omar G.](https://uploads.teamtreehouse.com/production/profile-photos/10444292/micro_pic.jpg)
Omar G.
3,620 PointsI think he means if he always has to re-size the images.