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A Guide to Image File Types & When to Use Them

One of the problems no one warns you about when you start your own business is the abundance of computer lingo you need to know, or at least convincingly pretend you do!

If you’re a small business owner creating content for yourself, it can be difficult to know what all those numbers and letter extensions mean when creating files, and sometimes googling the answer just gives you back more computer jargon.

As designers creating content for both digital and print, learning the ins and outs of file types and formats, and when each is relevant is essential to making sure the content we create is of the highest quality at all times. Nothing says unprofessional like pixels!!!

This month we’re breaking down the file types available to you, the differences and what projects each is most relevant for so you can make sure you’re creating or requesting the most suitable files.


These are terms you will probably have come across numerous times when looking into image file types, especially if you’ve investigated getting a logo made.

So what is the difference?

Raster images such as JPEG, PNG and GIF files, are composed with a series of small squares called pixels that together form a complete image. If you’ve ever seen one of those artworks where the artist has compiled a mass amount of small photos and arranged them by colour to form one large image you’ll have a fairly sound idea for how this works!

These pixels have defined proportions depending on the resolution of the image, and when the image is stretched or shrunk the program will erase or add pixels of similar colours to their surrounding to best accommodate the space. The limitations of pixels and process is what creates “pixelation” in an image.

All images online and in print are raster images, which makes sense when you consider they way they are created or projected. Our screens are made up of a series of small lights that are capable of changing colour to project the information it reads. Likewise, printing involves the laying down of a series of small coloured dots onto the paper to create a final image.

This also makes it essential when working with raster files that your original file is created and saved at the correct dimensions for final representation so as to maintain the best possible quality.

Vector Files such as AI, EPS and PDF are much more flexible and ideal for images that require regular resizing. They are created using proportional formulas instead of pixels, so that the computer can redraw the image at any size (anywhere from the size of a postage stamp to being large enough to stick on the side of a building) without losing any detail or quality!

Creating your branding and logo files as a Vector is essential for this reason, and is why we always provide our clients with the original vector files when a project is complete!


Whether you’re creating content yourself or speaking to your designer, you’ll probably have come across the term DPI/PPI before.

The required DPI (Dots per inch) or PPI (Pixels per inch) is different for different applications, and determining the correct saturation of dots is essential for maintaining high quality images throughout your marketing.

The most essential thing to determine is if your image is to be used online or in print;

Web images are displayed at the low resolution of 72dpi. While they look incredibly clean on a screen at this resolution, the same isn’t true for printing.

Printed files should be no less than 300dpi. This is why it’s essential to invest in high quality image files; whether that’s purchasing stock or creating your own to put on your printed materials. Ripping images from the internet, or attempting to resize them for your project will only ever get you blurry, pixelated images.


JPEG [Joint Photographic Experts Group]

Probably the most commonly used image file type, especially for online use. The quality of a JPEG image decreases as the file size decreases, so for this reason it’s essential to pay attention to the file size and resolution when using or creating a file of this type for a project.

They are most suitable for images being used online, in Microsoft Office documents, or for documents that are intended to be printed at high resolution.

PNG [Portable Network Graphics]

As the name suggest, PNGs for great for use on interactive platforms such as web pages. While they are ‘lossless’, meaning they are able to be edited without losing quality, they are still of low resolution and so are not suitable for print.

The added benefits of a PNG, which make them amazing for online use, is that you are able to save your image with a bigger range of colours on a transparent background.

GIF [Graphics Interchange Format]

GIFs are most known for their animated form, which makes them a popular choice for blogging sites or use in banner ads.

The file size of GIF files are dramatically smaller than other file types due to the limit on colours they are comprised of (GIF files are formed from a select 256 colours in the RGB colourspace). This may sound like a setback, but the smaller sizes make them ideal for web projects where quick load times are a priority.

TIFF [Tagged Image File]

TIFF files are large raster files that don’t lose quality. You can copy, re-save or compress the files without the original image data being impacted as they use “lossless compression”.

They are popular most familiar to photographers, allowing for extensive editing without impacting the original photograph.

Whilst the ability to maintain and recover quality after manipulation is great for editing photos for print, you should avoid the use of TIFF files for online use as they will have a devastating impact on loading times.

PSD [ Photoshop Document]

This is the default image file for documents created and saved in Adobe Photoshop. PSD files contain layers that give more control and smoother processing when editing images.

PSD files should primarily be considered a “working file” and used for generating a finished image. The final file should be exported as one of the above raster images, depending on the final use.

EPS [Encapsulated Postscript]

A vector format file, EPS are designed primarily for high-resolution graphics intended for print and can be created in most design programs. EPS files are universal in that any design editor is able to open them, meaning that if you need another designer to be able to access or edit your image you can rest assured knowing they can perform their job even if they haven’t upgraded to the Adobe Suite.

AI [Adobe Illustrator Document]

AI is the vector file produced in and saved from Adobe Illustrator, and is by far the most reliable type of file for images in all projects in the range of online or print. It is also the easiest to manipulate.

The program itself is used to create vector artwork (and is most likely where your logo was originally created), and is capable of exporting the image information in all the other file types, giving you and your designer the freedom to produce quality content for any project.

PDF [Portable Document Format]

A product of Adobe, PDF’s were created with the intention to give users the freedom to view detailed information from any application, on any computer, with whomever or where ever you want. Unlike other vector files, PDFs along with the free software Acrobat Reader allows anyone to be able to view and make minor adjustments without design editing software. PDFs are great for ease of sharing and communicating between other parties.


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