Optimal size of pics for this site? Q & A

[JoolsW]

Q? I've been looking for 'site recommendations' regarding the preferred image size for photos on 'our' site.
I'm very used to optimising and sizing images for particular purposes. For example for web use and forums like this I usually set dimensional size to 1200 pixels in the longest dimension and optimising at 72dpi. (Obviously for print I would set differently).
I know many people don't know (or care) about this. Perhaps the site automatically optimises images. Any info? A?

 

[Thiophilos]

Q? I've been looking for 'site recommendations' regarding the preferred image size for photos on 'our' site.
I'm very used to optimising and sizing images for particular purposes. For example for web use and forums like this I usually set dimensional size to 1200 pixels in the longest dimension and optimising at 72dpi. (Obviously for print I would set differently).
I know many people don't know (or care) about this. Perhaps the site automatically optimises images. Any info? A?

DPI is irrelevant. Try setting the DPI to 1 or 1000 and see what happens.

(Nothing will happen.)

 

[JoolsW]

Perhaps you didn't understand the question.
Here are two identical images, one set at 72dpi, and the other set at 20dpi. Everything else is identical. I'm sure you can see the difference! "Nothing will happen."? Something does happen of course. Obviously the 20dpi version is pixilated. So many people just don't 'get' image resolution.

 

[snowbear]

I try to post mine to Flickr at 300 DPI, though I have some at 72, and some at 240.
As far as image size, I go 800x600.

 

[Thiophilos]

Perhaps you didn't understand the question.
Here are two identical images, one set at 72dpi, and the other set at 20dpi. Everything else is identical. I'm sure you can see the difference! "Nothing will happen."? Something does happen of course. Obviously the 20dpi version is pixilated. So many people just don't 'get' image resolution.

View attachment 277678
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We are probably talking about different things. When Exporting from Lightroom Classic, it is possible to specify a Resolution. This setting does not affect the image at all. It only affects its metadata.

Exported at 2 pixels per inch

Exported at 1000 pixels per inch

They are identical.

No idea how you processed your images.

 

[smoke665]

You can post an image at full resolution, the problem is that for those of us not lucky to live in the modern high speed age it takes to long for the image to load. A better choice is as Charlie mentioned above, these are the setting I use with a resolution on the long edge of 900-1200, depending on the original resolution to keep my file size under about 700k for faster loading

 

[Thiophilos]

You can post an image at full resolution, the problem is that for those of us not lucky to live in the modern high speed age it takes to long for the image to load. A better choice is as Charlie mentioned above, these are the setting I use with a resolution on the long edge of 900-1200, depending on the original resolution to keep my file size under about 700k for faster loading

OK. My bug pics were 1500 on the long edge but output at 80 quality. The file sizes are 700k.

 

[JoeW]

I no longer post original photos on this site. I tried downsizing--and it was usually a very frustrating experience (either mediocre quality or having to try and downsize 3-5 times to hit the "sweet spot." What I do know is a screen capture of a photo--never the photo itself. The screen capture appears to be appropriate size 90% of the time.

So to answer an original question, NO, the site does not automatically adjust photos so they'll fit. Until I used screen captures, I would say about 80% of the photos I tried to post were rejected as too big.

 

[JoolsW]

The whole point is that on any site, the images have to be stored. -That is the digital information. The Standard resolution for screen display is 72 dots per inch (Pixels per inch). If people are using higher ppi, they are using more resources than is necessary, any higher res won't show on screen because screens are limited in pixel res. All they're doing is clogging up the system. Adobe has an excellent resource explaining all this. see below, I recommend it. (What Lightroom does is only of importance to Lightroom users). My images were simply set in Affinity Photo, but it's little different in Photoshop. Just use the Image Size routine.

In the past I wasted too much breath explaining to lazy clients (and some ignorant photographers) about resolution, image resolution needs to be set for the intended end-use, e.g. for web and screen, 72 pixels per inch, and for high quality Offset printing 300 ppi. You shouldn't need screen capture, Image editing programs have Image Size routines. And we should all have and use optimisation software, where you set res and quality. In Affinity you do the same as PSD -Image Size, and like PSD it has excellent export options to optimise at various qualities and various formats.

The Sabre pics above are 115kb and 61kb at 800 pixels wide respectively. Your file (Thiophilos) sizes are much larger. You don't get any better on-screen quality for the larger digital sizes, it simply uses up more disk space. I simply set the image size I want and save it with 'opt' appended to the filename. I still have my high quality original. As photographers we all should be aware of image digital sizes eh? Obviously the image pixel dimensional size and PPI (DPI) are directly related. Changing one will affect the other. If you care, look at:

Pixels Per Inch & Pixel Density | What is PPI Resolution? | Adobe

Getting your PPI resolution right can make or break your digital photos. But what actually is pixels/inch, and why is it important? Find out with our complete guide.

www.adobe.com

Apologies if I seem to be 'lecturing', (especially since I'm a newbie here), but it's simple knowledge that's useful to us as photographers.

 

[Overread]

Jools I think you keep mixing up the dpi and ppi in your posts. Dots Per Inch is a value only used by printers, it does nothing for digital display. Of course your software that you are using might combine dpi and ppi and even the Adobe article notes that some software swaps the terms over now and then.


Personally I just set images to 1500pixels on the longest side for landscape and 1000 pixels on the longest side for portrait; both in Photoshop and then just resize. I used to use 1K and 500, but in general screens for PC today are much larger whilst phone/tablet screens are might higher resolution.

 

[Thiophilos]

@JoolsW - Did you notice that my two pics looked the same even though one was 2 dpi and the other was 1000 dpi?

The DPI settings are only used by some printers or by Adobe Acrobat when compiling PDF files. Otherwise the DPI metadata is ignored.

My pic size is generally 1600 wide. It is good to have generously-sized photos in a photography site, as long as it doesn't overly encumber the system.

The bug pics are 1500 px wide and on my monitor at 100% they display at about 110 dpi. They don't come close to filling the screen. It will be different on other monitors and on phones.

 

[JoolsW]

I'm mixing up nothing. The terms are interchangeable. DPI is a very common term, I used both terms because some people like PPI and others prefer DPI. I used both the terms on purpose.
Believe me, I've been there done that!
Screens, the SIZE of the screen is immaterial, it's the resolution that counts. Prepping for screen viewing one has to realise that the images could be seen on a wide variety of screen sizes, so we compromise, that's why we generally default to 72 ppi.

 

[Thiophilos]

I'm mixing up nothing. The terms are interchangeable. DPI is a very common term, I used both terms because some people like PPI and others prefer DPI. I used both the terms on purpose.
Believe me, I've been there done that!
Screens, the SIZE of the screen is immaterial, it's the resolution that counts. Prepping for screen viewing one has to realise that the images could be seen on a wide variety of screen sizes, so we compromise, that's why we generally default to 72 ppi.

It's wonderful to see such assurance.

The 72 PPI Web Image Myth - Photo Cascadia

The purpose of this article is to explain why the pixel per inch setting you assign your web images is irrelevant, despite that we’ve been told 72 pixels per inch resolution makes your images look best on screen, allows them to load quickly and keeps thieves from making large prints of them.

www.photocascadia.com

 

[JoolsW]

Happy to oblige mate.

Re: the link to Photocascadia.

This presentation is essentially meaningless! And it is misleading. Pixel count and image size are related and given certain settings, are locked together. Simply put, an image that is a certain dimension, will not DISLAY any better if it is at 300pi than if it's 72ppi. Because we are limited by the screen resolution (your monitor). This is the point... It's your SCREEN PIXELS that are showing your image.

Simple isn't it! And DPI has nothing to do with inkjet printing! It is about high quality Offset printing where images should be 300dpi AT FINAL SIZE -(to do with sampling rate of the platemaking device etc).

What this feller completely ignores is that we need to allow for all sorts of different output devices. If we follow his example an image set for high PPI that might be okay on a large 27" monitor will be far too wide for a small tablet display if it's a 300ppi image with no contrained dimensional size, consequently involving a lot of scrolling. The pixel PPI is limited by the screen resolution of the output device.
He confuses the number of pixels with SIZE of pixels! Sorry, he is completely confusing things! Pixel SIZES do not change! To do proper comparisons you must CONSTRAIN THE IMAGE SIZE, (in ppi or mm or inches) whilst changing the ppi per inch. THEN you'll get the correct comparison.

 

[smoke665]

Apologies if I seem to be 'lecturing', (especially since I'm a newbie here), but it's simple knowledge that's useful to us

I guess I'm a little confused because in your OP you asked for TPF site recommendations to which many responded, but you've taken your own post off the rails with DPI, PPI, Resolution, lectures, etc.

The simple answer to your question about site recommendations is to do what most of us do, upload a larger resolution image to an offsite location like Flickr, copy the BB code for the resolution you want to share, and simply past it in your post. Doing this avoids having your image compressed or otherwise distorted like so many sites do.