Best Image Size/Resolution for PPT

Ok, so I've been trying to do some research on this topic, and now I'm more confused than when I started. Some say the dpi of the image matters (72, 96, 150 have all been recommended). However, some (more reputable) sources have stated that the dpi doesn't matter for PowerPoint presentations (at least displayed/projected); rather, it's more about the pixel size of the image (recommended 1024 x 768 as a standard).

I also know the size of the image and the resolution are mathematically related. For example, an image that is 1200 pixels in width and 300 dpi is about 4 inches in width, whereas at 72 dpi, you're talking a little over 16 inches in width.

Here are my questions:

1. Let's say I start with an image that's huge, 3872 by 2592 at 300 dpi. I want to re-size this image to be full screen in my presentation when it's projected at 1024 x 768. If I re-size the 3872 to 1024, keeping the proportions the same, does the dpi matter for quality, file size, neither, or both?

2. How does setting default compression settings in PowerPoint affect any of this? For example, let's say in the above example I re-sized to 1024 in width, but I left the dpi alone at 300. Then, in PowerPoint, I used the compress images function to take it down to 150 dpi. Have I changed the size of the image now?

3. How does all of this impact working with Articulate products (versus displaying a PowerPoint presentation via a projector)? For example, I've seen the job aid where the image size is recommended at 720 x 540, with scaling options turned off. However, I personally don't like to lock the presentation, because as a learner, I like having control over the size, in case I want to see the text larger, etc.

4. I see the "slide show settings" in PPT can be used to set the presentation size to 1024 x 768 or various other choices. Is there a recommendation for setting the size for Articulate Presenter output?

I'm a little all over the place, sorry! If anyone has an answer or could point me to a good resource, I would much appreciate it!



7 Replies
Rich Johnstun

Articulate only publishes in 4:3 at a resolution of 720 x 540. Yes, PPT can handle other settings, but Articulate cannot. 

Standard image dpi for web publishing is 72dpi. Standard for printed media is 300 dpi. 

If I want a full size image for an Articulate slide, I make it 720 x 540 at 72 dpi. I do everything at 72dpi unless it is going to print media. 

Rebekah Massmann

Hmmm. I understand the 4:3 constraint, but you can change the resolution via Slide Show-->Set Up Slide Show-->Slide show resolution.

I tried 800 x 600 and 1024 x 768, and both appeared to publish successfully. I believe in the past, it has defaulted to "Use Current Resolution (which for me is 1280 x 1024).

Phil Mayor

Rich Johnstun said:

You can change the display resolution in PPT and even work in that, but Articulate still publishes the slides as 720x540. If your user makes the presentation full screen and is running a higher resolution, the image is stretched/scaled to fit the screen by the browser. 

Agree with Rich not much point changing the slide size, as it will be loaded as a 720x540 swf.  If you scale down a large image in ppt (because ppt does not resample the image) you increase the DPI.  I work in 96dpi.  You can once you are happy globally change the dpi of all images by choosing compress pictures

David Celaya

And remember, DPI stands for Dots Per Inch, and is a printing term, as in how many dots of ink will there be in one inch of a printed image (vertical or horizontal). PPI is pixels per inch, and is similar, but is used to reference images seen on a screen.

The key is that you said, "...I want to re-size this image to be full screen in my presentation when it's projected at 1024 x 768."

If its going to be seen at a max resolution of 1024x768, then using an image that is any larger pixel wise...or any higher that 72 (or 96) ppi, probably wont matter in terms of image quality to the viewer. The best thing to do is test the end results for yourself. Place the large (3000px plus) photo in the ppt, resize it down to what you want, and then if you can, on another slide bring in a copy of the same photo that you re-size before you bring it in (with photoshop, or any other pixel editor). Then you can view the Articulate output of the two versions side by side.

Lastly, don't forget that you can adjust your compression options under "Presentation Options".