This is something I found confusing to begin with, so this post is a bunch of notes to myself.

A big part of why I found this confusing is that coming from an old school background in Dreamweaver, I was used to thinking in terms of choosing my image sizes – typically 500 – 700 px wide or 300 – 500px high, and posting them like that.

I was also used to setting the text formatting as a fixed style, but the text in WordPress can be quickly changed – eg. the text on this site is all set to show as purple, but I can override that by choosing a different colour in the formatting tools bar like orange or green

As the images the media size settings are not determining the size of the images, I can upload my photos at the full size. (which for many of my photos is 4608 x 3456 px)

All the image setting sizes are doing is re-sizing my big pics down to the selected sizes, or re-sizing small images up to them.

This photo appears here at the 300 x 300 px medium size (I had that size selected in settings at the time, but have since gone up to 350px.

And if you click on it it will fill up your screen size because I had the large size set to 9999 x 9999px – or as big as your screen size can show.


Like turning the text orange, I can drag the image to look bigger here on this post than the 300px size it is set to display at – here it’s dragged out to 450px. But if I do this too much the image will look low res and poor quality, because we are only viewing the medium sized thumbnail, not a smaller version of the original hi-res image.


To change the image settings, go to:

Dashboard – Settings – Media

(This can be left open in a separate tab and quickly changed while editing the site)

The default settings on WordPress are:

Small 150 x150 PX

Medium – 300 x 300 PX

Large – 1024 x 1024 PX


I have gone with:

Small 150 x150 PX (I’m not using small thumbnails on the site at this point)

Medium – 350 x 350 PX (seems to be a good display size for image galleries)

Large – 5000 x 5000 PX (none of my photos on this site are over 5000px wide so this is effectively as big as can be displayed)

Regenerate Thumbnails

I haven’t tried this yet, but may do later – apparently this plug can regenerate the thumbnails for your image attachments. Handy if you’ve changed any of your thumbnail dimensions (via Settings -> Media) after previously uploading images or have changed to a theme with different featured post image dimensions

This site covers more of this stuff –


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