A Photo - how to see the file size of a photo?

[Guest]

In Photoshop the file size of the photo is clearly shown. Does AP show the file size somewhere?

In AP across the top I can see the dimensions and then there is a figure xxMP - what does MP stand for? This seems to relate to the file size (but isn't the same as the file size shown in the Finder) and surely it would be MB?

[Dan C]

Hi Markeeee

The MP in your screenshot is the MegaPixel count of the image, unfortunately there isn't the option to view the size of the file in realtime from within the app currently.
I'll move this thread to Feature Requests for our devs to consider implementing!

[Fixx]

Thing with file size is that it depends. Usually though you would like to know the size of uncompressed TIF, as it meters straight resolution related size. When you do more photo editing it will not matter though as you can check resolution/size/dpi with image size command. 

If you just want to know size in megabytes, you know afphoto file size can be very big, while JPEG size can be very small indeed..

You can check file size by selecting export and checking it in dialog box (though this may not always work with bigger file sizes.. it jams).

[Guest]

On 10/3/2018 at 2:27 PM, Dan C said:

The MP in your screenshot is the MegaPixel count

What's MegaPixel count? I've used Photoshop for 20 years and never heard of that.

On 10/3/2018 at 2:27 PM, Dan C said:

I'll move this thread to Feature Requests for our devs to consider implementing!

Thanks. I think this would be very useful.

[walt.farrell]

MP = MegaPixels. Photos are made up of pixels, and have dimensions like (in your screenshot) 255px by 425px, or perhaps 2000px by 1500px. Multiply the two dimensions together to get the total number of pixels, divide by 1 million (roughly) to get how many million pixels (mega pixels) the photo contains. (As with some other computer-related measurements, "million" in this case might actually be 1048576, not 1000000.)

As far as wanting to know the size, there are many sizes that could be relevant, and it would be hard for the program to guess which you might want:

1. The size (as saved on disk) of the file you originally opened.
2. The size (as saved on disk, but uncompressed) of the file you originally opened.
3. The size in memory of the file as you've currently edited it.
4. The size the file would be if you saved it.

1 through 3 are easy to provide, if  the program knew which you wanted.

#4 depends on what format you might decide to use when exporting or saving it, and (for export) on various options you might choose at the instant you decide to perform the export. For example, what format will you choose (TIFF, JPEG, PDF, PSD)? The file format will have a large effect on the file size.

If you choose JPEG, what quality value will you choose? That  will determine the kind/amount of compression that will be used which determines the final file size. The other file types may have their own considerations that will affect the file size. (And in many image apps, if saving in TIFF you would have a choice of whether to use compression or not, and possibly what kind of compression to use. Affinity Photo does not (today) give you that choice, but it might in the future.)

So if you were to want #4 I don't think there's any way you can really tell or even approximate the file size without actually going into the Export dialog and specifying the file type and other associated options. At that point the application can calculate the approximate size.

[Guest]

Hi Walt, many thanks for your great explanation.

Photoshop displays the" file size"* in the user interface. I've always found it useful to have an indication of the file size. Often to quickly see if someone has sent me a web image for a printed document, or to see if my image is getting way too big to handle in desktop publishing software.

I understand the file size isn't shown in the user interface in AP - so how do I check the "file size"? Unlike Photoshop it isn't even shown in the Resize Document window. This seems strange, because often it is necassary to change the dimensions or dpi to reduce the file size - but the Resize Document doesn't show the file size.

*I presume Photoshop file size is the size of the file if saved to the computer with no compression - basically an uncompressed Tiff.

 

[walt.farrell]

54 minutes ago, Markeeee said:

I understand the file size isn't shown in the user interface in AP - so how do I check the "file size"?

If you're going to end up with a non-Affinity file type (JPEG, TIFF, PSD, PDF) you could start an Export operation, set the file type and appropriate options, and see what file size Affinity provides.

[Guest]

So there isn't any way to see the file size in AP without "pretending" to Export it? I can't even see the file size in the Document Resize window. This all seems very odd coming from a Photoshop background.

Once again thanks for your help

[walt.farrell]

You're welcome. If there's another way I don't know if it, but it's never mattered to me as I consider the info irrelevant until I'm ready to export. But I can understand if your workflow and needs are different

[Fixx]

17 hours ago, Markeeee said:

So there isn't any way to see the file size in AP without "pretending" to Export it? I can't even see the file size in the Document Resize window. This all seems very odd coming from a Photoshop background.

No, there is no file size indicator in AP. 

I found that indicator useful when I started using Photoshop long time ago, but since then my work flow my has evolved. I usually know what size I am working with and if I need precise number file size is not readable indicator anyway. CMD-I or dummy export can tell me exact resolution/file size, latter being useful only to JPEG export as real file size does matter only in web work.

[Guest]

When I do "cmd I" in AP it inverts the colours. It doesn't give me an Information panel. Or are you refering to doing "cmd I" in the Mac Finder?

[Fixx]

Ah sorry, I meant CMD-OPTION-I (=image size)

[Colecowes]

Has this subject been considered - I always need to know the current size of the file on the disk?

[porkunit]

I come from a photoshop background doing prepress for many years. Resolution and size are critical to preparing files for print. I wish affinity had this option to see resolution and physical image size. Since Affinity doesn’t have this, just open the file in web program www.photopea.com. It has a photoshop type interface and has the option we’re looking for until Affinity catches up. Plus, it is FREE! Try and you’ll be amazed.

[Fixx]

10 hours ago, porkunit said:

I wish affinity had this option to see resolution and physical image size. Since Affinity doesn’t have this,

when I press cmd-option-i the resulting window magically tells me size and dpi!

[John Rostron]

On my PC, Ctrl-Alt-I brings up the Document Resize dialogue which tells me the dimensions (pixels by my default) and the dpi. It does not give me the size of the file on disk.

John

[PaulEC]

If you go to export the file it will display an "estimated size" (obviously depending on the file type /settings you are using).

[Fixx]

19 hours ago, John Rostron said:

It does not give me the size of the file on disk.

@porkunitdid not ask it.

[John Rostron]

These discussions are foundering on what is mean by 'size'. Different contributors are interpreting it as either the physical size on disk, typically measured in kilobytes (KB) or megabytes (MB) or the area of the image, typically measured in mega pixels. (MP) More experienced members use 'file size' for the former. @walt.farrell explains it well in his message above.

 

John

[Old Bruce]

John Rostron got two of the three I think of when someone asks about 'File Size'

Bytes,

Pixels,

inches/cm/picas.

Sorry to say I guilty of not specifying when I use File Size,

[LaPellesFactory]

I agree with @porkunit above. Memory usage of a photo as measured in bytes is critical in most print production. Generally, higher-quality print requires a 300-dpi resolution, but files from digital cameras and most stock photo services come in at 72 dpi. These must often be resampled to 300 dpi before use in printed documents. When resampling, however, the photo's resulting memory usage in bytes cannot be any bigger than that of the original or the art will lose clarity when printed.

For example, a 2592 x 1944-pixel image from a digital camera uses 14.4 mb of memory and, when printed at a resolution of 72 dpi, will yield a 36 x 27-inch print. When resampled to 300dpi, the same image prints at roughly 8.5 x 6,5 inches. You can't add to the number of pixels in the art and maintain image clarity, so you can't simply use the resize command to upsample to 300 dpi at the same pixel dimensions as it was at 72 dpi.

Technology changes quickly and this issue probably doesn't matter as much to designers whose product is used exclusively online. But there are still thousands of people working in the print industry who need to be able to check memory usage quickly and easily. If the Affinity suite is going to be a serious alternative to Photoshop (and I sure hope so!), the ability to see image memory usage (the "image size" menu item in Photoshop) is essential for a lot of users. It's a curious and unfortunate omission in a very promising product.

[frebe]

I am a print designer too and file size ie. bytes on disk (NOT dimensions) is critical to resizing images for print without resampling too much - which changes the image. 

The process I use to size an image for print is:

- change the dpi to 300 (print optimal) and, in the same step, adjust the image dimensions until file size (bytes, MB etc) is as close as possible to the original file size. If you don't do this you are adding or removing data which you want to avoid. This is why file size is useful in the document resize dialog so that you can make sure you are not adding too much resampled data.

- Then you can make your image smaller or crop to requirements. This is always done in a separate step once you have the dpi set with same file size. If you change dimensions and dpi together you have less control over image quality.

- It would be really useful if Affinity included the original file size and new file size in the Document resize dialog for print designers!

PS If anyone know a better way to to change dpi without resampling too much I'd love to know - this is what I was taught

 

[Alfred]

Welcome to the Serif Affinity Forums, @frebe.

12 minutes ago, frebe said:

- change the dpi to 300 (print optimal) and, in the same step, adjust the image dimensions until file size (bytes, MB etc) is as close as possible to the original file size. If you don't do this you are adding or removing data which you want to avoid. This is why file size is useful in the document resize dialog so that you can make sure you are not adding too much resampled data.

If you have an image which is 720 px × 720 px @ 72 dpi, its print size will be 10″ square. For the same print size at 300 dpi you need the pixel dimensions to be 3000 px × 3000 px, and I don’t see how you could achieve that without adding millions of extra pixels.

[frebe]

Hey Alfred, you are correct. You can’t INCREASE the resolution AND image dimensions of your original file for print production. We only ever reduce dimensions in order to increase dpi as I described. That is why we need to see the file size in the resize dialog to use as a guide to how much or little data we are adding to the file. 

For basic photos, saved as 72dpi jpegs, the process I have described is how we change the dpi to 300 without resampling too much- You always have to REDUCE the dimensions to increase the dpi.
300dpi is the requirement for high resolution quality printing of photos and raster images. We need to set exact dimensions of the final printed output at 300dpi.
if the original photo is too small (ie total bytes) there is nothing we can do with it - it will be pixelated if we enlarge it in the printed output. 
Photos produced on professional cameras are very high resolution so we can reduce the dpi and the dimensions to suit. But you can never increase dpi AND dimensions without adding more pixels, and thus, distortion and noise, as you say.

I hope that makes sense - you are absolutely right - This is actually hard to explain in words😂

[Alfred]

7 minutes ago, frebe said:

We only ever reduce dimensions in order to increase dpi as I described. That is why we need to see the file size in the resize dialog to use as a guide to how much or little data we are adding to the file.

If you’re reducing the dimensions on output, you don’t need to add any pixel data at all. Using my earlier example of an image which is 720 px × 720 px, where a resolution of 72 dpi will give you a print size of 10″ square, increasing the resolution by a factor of 5 (to 360 dpi) will result in a print size of 2″ square without changing the pixel contents.