Lincoln is hidden in the low frequencies in the image. One way to filter out the high frequencies is to step back a bit from the display, another is to squint your eyes, resize the image, or just use a low pass filter in an image editor.

https://imgur.com/a/NK5GFGn

Or, if you're a myopic glasses-wearer, simply try on-off. I love this trick for images of all kinds because it allows me to apply a uniform blur, no computation required.

I can just let go of focus, like a thousand yard stare.

Thanks. I can kind of see it out of the corner of my eye if I move a bit further from the screen.

I guess that's what the pixelated portrait of Lincoln on the same page is then.

You might need to be further away (or try squinting).

Spatial frequency is often reported in cycles/degree. A cycle is one complete set of transitions (light->dark->light) and a degree is the angular distance (1/360th of a circle; about the size of your thumbnail at arm's length). These units are handy since they don't depend on the thing you're looking at or how far away it is.

Human spatial frequency sensitivity peaks between 1-10 cycles/degree, depending on how old you are, to see Ol' Abe, you ought to be far enough away that your thumbnail covers at least five of the tiles.

Thanks, I was able to see it by moving away from the screen a bit.

The small portrait is reproduced in the larger one. The pixels of the beard are around the bottom of the window, the ear is the lighter blocks to the left, and his right eye is her head in the center.

Thanks, I realised what the smaller portrait was after reading the helpful comments in this thread.

For me to see Lincoln, I tried holding my phone at arm's length; it was better when my friend held the phone and I stood back

You have to be far away (20m away for the original) or squint a bit/cross your eyes and the big picture starts looking like the tiny portrait of Lincoln that you mention.

You can also save that picture on your device and look at the generated thumbnail. Resizing it makes it a lot more obvious.

Cheers, I managed to see it eventually.

I feel terribly sorry for you... and then delighted for you once you see it!

Nope I still can't see it. Maybe downvote me a bit more because I can't see it? That might help.

Still, be nice to the Goblynne Queen.

Think how frustrating it must be to hear other people say how cool something is, while not being able to see it yourself!