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mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
When I texted a photo to my email, the attachment size was always 238 KB.

Recently I tried texting the same photo to my email, and the attachment size was 287 KB.

Short of paranormal activity, what could have caused this change? Does this mean my photo is corrupt?

I would appreciate any help.

Before anyone asks, I don't use iCloud Photos and never have.
 

Slartibart

macrumors 68040
Aug 19, 2020
3,146
2,821
Welcome to MR! Can you kindly elaborate on a few points:

On which hardware platform (model?) using which app (version?) you send a photo (in which format?) via a text message?

What do you mean by:
When I texted a photo to my email
Can you kindly explain step by step what you are doing?

Where do you get the information of the size of the photo from?

Besides the format - what type of photo - live picture, photo using portrait mode, etc. - is it?
 

mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
I go on text messages, and instead of typing a number, I just type my email!
The photo is actually a screenshot.
I find the size by downloading it from my email onto my computer.
 

Slartibart

macrumors 68040
Aug 19, 2020
3,146
2,821
I go on text messages, and instead of typing a number, I just type my email!
does your email account appears in blue or green?
The photo is actually a screenshot.
I find the size by downloading it from my email onto my computer.
Depending on the version of iOS - if you open this screenshot in Apple’s Photos and select the i in the circle in the menu bar to see the related information, what size is reported?

On what kind of computer do you download it via mail?
 

mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
If I open the "i" it says 287 KB. That is the new size on the MacBook Pro. I hadn't checked the "i" before, so I have no way of knowing.
I download it on a MacBook pro.
 

Slartibart

macrumors 68040
Aug 19, 2020
3,146
2,821
depending on the file system and the block size on each of them, the size of identical files varies between different systems.
If you copy the attached identical file from each of the two mails to the same folder on your MBP, do they still have slightly different file sizes?
 

macsound1

macrumors 6502a
May 17, 2007
835
866
SF Bay Area
I'm trying to understand. You've sent this exact screenshot file multiple times via iMessage from your iPhone?
Are you taking new screenshots or it's the same file that you send over and over again?
 

mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
It's the same file over and over again.
It always came out as 238 in the email. Now if I send it, it comes out as 287.
But is always the same file, which dates back to 2020.
 

macsound1

macrumors 6502a
May 17, 2007
835
866
SF Bay Area
Any chance that at some point you clicked edit on the file on your iphone? Image sizes are based on the content in them and if you accidentally did something like adjust the brightness, it could make a file size change.
 

lostless

macrumors 6502
Oct 22, 2005
488
103
When you say text, you mean that you put your email address as the recipient instead of a phone number? If so, your phone carrier has reprocessed the file. MMS never sends a the original file. It also strips all meta data.
 

cthompson94

macrumors 6502a
Jan 10, 2022
812
1,164
SoCal
I know this is slightly irrelevant to solving the specific issue.. but I noticed in one reply you mentioned a MacBook Pro, any chance you could just airdrop it the the Mac?
 

mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
When you say text, you mean that you put your email address as the recipient instead of a phone number? If so, your phone carrier has reprocessed the file. MMS never sends a the original file. It also strips all meta data.
Yes, that's what I did.
Does that mean the original file itself hasn't changed?
If not, then why is it suddenly being reprocessed differently?
 

lostless

macrumors 6502
Oct 22, 2005
488
103
no, the original file is still good and has not been changed. When you text to an email, your phone is using MMS messaging, like texting an android user. MMS is very specific on the specs Of an image being used so it works over that system. But instead of checking if your image is, (most likely not) your phone/or the carrier will just recompress to make sure it goes through.
 

lostless

macrumors 6502
Oct 22, 2005
488
103
Recompression doesn’t mean smaller file. It’s compressed compared to an uncompressed version. If it’s already highly compressed, you can’t bleed more data out. Now you have to use more data to preserve the compression artifacts. Basically, it creates an uncompressed copy and then recompresses with whatever algorithm it needs.
 

mpeg1

macrumors newbie
Original poster
Aug 25, 2022
8
0
The original file was sent multiple times.
This is what happened: Orig----Email----238
Orig----Email----238
Orig----Email----287
This is NOT what happened: Orig-Email-238-Email-287

Did the original file change?
 

lostless

macrumors 6502
Oct 22, 2005
488
103
If you are texting via MMS, its never the original file on the other end. The original file is never touched. It stays safe from where ever you sent it from.
Its possible that maybe your phone or phone carrier used a slightly different compression method one time and the other 238k may not even be the exact same size and may just be rounding to the same. Did a test and email via text and the file received was a few hundred KB larger. Still said the same size. Not the original file. As long as it looks good to you, then it did it's job.
The only way to keep the original file transferred is to email yourself (not text), or use a cloud drive, photos cloud, or airdrop.
 
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