Markag

My neighbor often Imessages me photos which are quite small on an Iphone screen. When I get especially excited about one I ask him to send me a larger version through email allowing me to view in Photoshop.
Yesterday he sent me a photo he exported a jpg from Capture One with "normal" compression.
The file I received, according to Windows Explorer was 1,576 kb in size and had me thinking it was of the smaller versions again.
When opened in Photoshop 25 it filled my screen and PS file size reported the file to be 212mb in size. 24.597 inches wide and 16.737 deep plus 300 Pixels/inch.
Interest peaked, I saved as, followed by exported as and each time when reopened in PS25 the file was huge.
Of other interest, perhaps, was that W11 explorer sees the save as file as 5,979kb while the export as shows 4,776.
I'll attach the original Capture One exported jpg to see if it gets by UHH specs.
And it did accept the file. When downloaded and saved to my desktop/opened in PS it still says 212mb ! ! !
Can anyone explain this.

(Download)

CHG_CANON Loc: the Windy City

How many times?

How many times do we have to explain the single most important aspect of a pixel-based digital image is the pixel resolution?

How many times?

How many times do we have to explain the file size in bytes (MB - megabytes) has nothing to do with the print / display sizes of a pixel-based digital image?

How many times?

Your attachment is 7379x5021 pixels wide & tall - this is the 'pixel resolution'. Yep, it will fill your screen. The fact you can attach and store the file to an UHH post tells you next to nothing, other than the file size is at (or less) than roughly 20MB. A quick detach and we see the filesize, on disk, 1.53MB.

What we can't see is all these immense file sizes you're quoting. Given you're referencing email attachments, we're left thinking your quoted PS observation are erroneous, as they're unrealistic. You should double-check and reconsider these PS observations.

The likely issue is that PS is 'reading' the hard-coded nonsensical 300 dpi value embedded into the JPEG. How many times? How many times do we have to say: there are no dots in a pixel based image? None.

Markag

Geez, grouchy today?
I have PS and LR and often struggle to get the file size down low enough to be accepted at UHH or sent through Gmail at their 20mb limit. My neighbor simply exports from Capture One and his file is 1.5 mb. I want to know how to do that ! ! !

CHG_CANON Loc: the Windy City

This post has been available since 2018, with a screen capture of a LR User Custom Export, making a 1-click repeatable process for any digital image, JPEG, in the 2MB range.

Recommended resizing parameters for digital images

Markag

Thanks

fredpnm Loc: Corrales, NM

CHG_CANON does an incredible job helping folks with their various problems, especially those who have made an honest effort to solve them themselves. Computers and their programs/tools can be tricky at times, but being determined to do one's homework before asking others to do it for you goes a long way to getting help when it really is needed.

You haven't done your homework...LR easily solves your 'getting the file size down' issue if you just follow the Export dialog. UHH has plenty of self-help topics, as CHG_CANON has so kindly pointed out, that address a good many 'how to' tools for using UHH.

We should be grateful for CHG_CANONs help when needed, not accuse him of being grouchy, especially when someone hasn't done their homework. His response to your inquiry is valid and true.

Markag

I said thanks and the link was explained very well. 2048 sounds fine BUT
What isn't explained is the photo I uploaded, when saved to my computer after uploading to UHH reports:
Width of 7379 Pixels
Height of 5021 Pixels
Resolution 300
Over 3.5x the recommended 2048 and is still a 1.5 mb file?

CHG_CANON Loc: the Windy City

JPEG quality. Look at the 1:1 pixel level details, especially transitions of color in the background greens. Our friends at Capture1 probably have a new & proprietary compression process, doing a really good (overall) process of removing unnecessary data to render a good looking image with a minimum of bytes of storage, even when you look closely at the 1:1 level details.

BTW: resolution 300 is nothing but a hard-coded piece of text, having as much meaning and impact on a pixel-based digital image as Resolution 200, or Resolution Shiney Object, or Resolution Squirrel ....

Frescaguy

For newbies and dummies like me keep repeating. Thanks for your continued assistance.

profbowman Loc: Harrisonburg, VA, USA

There are two adjustments to a photo size that you can control.

1. Reduce the size of the photo in pixels. If you begin with a size of 6000 x 4000 pixels (a total of 24 Mp) and cut the width and height by half, you will end with 3000 x 2000 pixels (6 Mp, which is 1/4 of the original size).

2. Then if you reduce the jpeg quality just a bit, the total byte size will also be reduced without a observable loss of resolution quality. But there is no firm exact equation for this reduction.

But for a practical example, I picked a photo without much thinking out of my repository. The first photo below represents the original version from the camera (6000 x 4000 pixels) with just a bit of adjustment for noise, contrast, and brightness.

The second photo was reduced to 1/3 the number of pixels on the width and horizontal sides (2000 x 1333 pixels). It has only a small amount of additional adjustment. The third one has the same pixel size as the second one, but it was saved at 90% of jpeg quality.

So, both adjustments can make a substantial change in the MB size of the stored file. --Richard

Original Size: 22.8 MB

(Download)

Pixel Size Reduced by 1/9: 3.42 MB

(Download)

Quality Reduced from 100 to 90: 0.61 MB

(Download)

Retired CPO Loc: Travel full time in an RV

I think you need to step back a bit! Yes, Paul is pretty sharp about most photography stuff. And, yes, he helps a lot of people. Almost always with a BIG dose of snark. What makes him think that this particular UHH'r knows or has seen this subject here before? Or a lot of other subjects covered or not here on UHH. Accusing him of being grouchy is not simply an accusation, it's simply fact!
Some people (me) don't have the head for this stuff and struggle along trying to make some headway. Snark, from you or Paul does NOT help! The best response to a question here would be no response at all, unless the snark can be held to a minimum!!

User ID

KISS solution:
Choose "Save for Web".

larryepage Loc: North Texas area

Setting aside all the low level snark and smoke, there is a valid question underneath your observations around file sizes. The image dimensions as reported above are very similar to what I would expect to see from a full resolution, minimally compressed JPEG produced by my D810. Depending on actual image content, those files tend to range between about 20 and about 30 MB when they come from the camera.

Some of the file sizes you report could come from a highly compressed version of those images, if content is fairly simple (which your flower is). The 200+ MB reported file size is not reasonable (although I've seen it happen) and probably resulted from a really wronge file block allocation somewhere along the way.

Many factors affect the amount of space allocated to storage of any file on a computer. Most allocations are accomplished efficiently. Some are not. This is a case where there is too much that you don't know about how the file was handled before it got to you for you to know what the "right" size should be. The absolute best thing to do is to have a nice hot chocolate (or preferably a mocha) and not let it get you too excited.

Markag

Best solution so far. Appreciate it.

SalvageDiver Loc: Huntington Beach CA

Yes, but the explanation is IS NOT simple.

CHG_CANON is correct when he says that there is no direct correlation between file size and image size, with the caveat of saving files using compression, lossy or lossless. JPEG is a lossy compression file format.

Now a bit of a technical discussion

The very basic process for saving a JPEG is:

1) Original image is broken into image blocks (8x8 blocks)

2) Via the Discrete Cosine Transform, transform the image from the spacial domain to the frequency domain and quantize the DCT coefficients. The level of quantization determines the amount of compression.

3) Strip the high frequency content (luminance and hue) from the image. The content removed is, generally, not noticeable by most viewers.

4) data compression (Huffman encoding)


So the image loses information and is highly compressed in the frequency domain resulting in much smaller files for a given image size. Both, the frequency content and the amount of compression (user selectable) determines the file size (not image size). For example, if you were to save a pure white image with the same image dimensions and same compression factor as your flower image was stored as, the white image would be smaller because there is no high frequency content in it.

When the image is viewed, the software decodes the remaining info in the jpeg file and displays the lossy image. In most cases, the information lost is not perceptible to the viewer.

So, why work in the frequency domain? Representing an image in the frequency domain requires MUCH less data than in the spacial domain. If you have a technical background, you’ll know that time series such as a sine wave can be described with much less data in the frequency domain (via the FFT) than in the time domain. JPEG’s use this same advantage.

This is why JPEG file size and image size DO NOT correlate!

Now back to the practical discussion.

There is 110MB of image data compressed into your 1.6MB JPEG file.

When you load your JPEG into Photoshop, Photoshop decodes the compressed image and stores it internally as 24-bit pixels, uncompressed (8 bits of R, 8 bits of G and 8 bits of B). In your case, your 1.6MB file is expanded to an uncompressed 110MB file internally. That allows PS to manipulate each individual pixel in the image. So here is a basic calculation on what the image size in bytes should be.

(7379 x 5021pxl) x (24 bits/pxl) / (8 bits/byte) = 111MB

Which corresponds to PS’s doc size.

AND, if you save your file as an uncompressed TIFF file, the resulting file size is 111 MB.

If you convert your image bit depth from 8-bit to 16-bit, the resulting TIFF is 222MB.

Hope this helps,
Mike

PS: Feel free to PM me if you have any specific questions about my response.