Image formats at Pixmac: what do we offer and how do you work with them?

October 4, 2010, Author: Lucie Navrátilová, Categories: General news, Showcase, Tips & tricks, Tutorials

There are two standard formats of images: Raster and Vector. Let’s describe them both.

Raster graphics consists of picture elements, also called pixels. We can imagine it as a grid of dots, and every dot has its own colour. A basic image can be made by 4 dots only, as you can see in the following image.

If the amount of dots is sufficient and they are small enough, our eye percieves them as a continuous image. Such a picture can be our photograph or also some graphical projects are made in raster graphics – the designer can affect every dot of the image exactly how they need it.

However, there is one problem connected with raster graphics. It is in resizing the image. Let’s talk about our 4 pixel image again. What happens when we don’t want it 2×2 pixels, but 3×3? The subject of the image must remain the same but we need to show it in higher resolution (it means we have to show it in more pixels). What colour should appear in our “new“ pixels? Black, white, gray? And it is even more complicated with real photographs – there is much more options. There are some algorythms that can get the acceptable colour – some of them can work with photographs, some give better results in illustrations with sharp edges. But the results are never perfect, there is always some loss of information in the image.

Let me show you two images of a woman’s face: The first one is original. It was expanded by mere zoom. We can see sharp edges of some of the picture dots – especially there where the head with hair of the woman ends. The second one image shows the same photo with more image dots. We don’t see the angularity anymore, but the image is much more blurred and we have lost some information in the image.

This problem is solved by vector graphics. The image is saved in the form of geometrical shapes – circles, elipses, rectangles and splines. There are several advantages: besides the easy matematical recount of sizes you can also work with each object separatelly (compared to the raster image where choosing each object is quite complicated), even the memory requirements are much lower. But we cannot make the vector format from a standard photograph or another complicated image easily – algorithms for conversion of complex images into the matematical description are too complicated. So vectors are usually used for easier pictures – they are best suited for graphic designers for their layouts, either for their websites, programms or pictures for their T-shirts etc.

You can find both formats on Pixmac. All images can be downloaded in JPG format, which means in raster graphics. Illustrations are also offered in a vector format in which they were originally made. Usually they are in SVG format, sometimes you even get a ZIP file with more formats (usually EPS and AI). So it is up to you whether you choose vector original file or JPG preview of the image.

One hint: You can filter vector images in our Power search.

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1 Comment

  1. Beneficial

    Claire I. Jiang, April 8, 2011 @ 12:31 pm

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