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Basic question on image size/quality


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Does anyone know why the jpeg mb changes when I move images between Photos and Affinity?

It also changes when I move from Affinity to Photos, without editing.

 

Another frustration is when exporting from Photos directly to email, the mb is dropping every time (I am making the setting 'actual size' in email settings)

 

Any help would be appreciated.

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How are you checking the file size of photos stored in Apple Photos? If they are in a Photos library, there are several copies of the image stored there, plus references to them in library support files. Only if you use the 'export unmodified original' option in Photos are you guaranteed of getting the original 'master' file.

All 3 1.10.8, & all 3 V2.4.1 Mac apps; 2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.8; Affinity Designer 1.108; & all 3 V2 apps for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Thanks for your reply, R C -R.

 

I am checking the file size in photos by clicking 'get info' I am then clicking and dragging the images to a desktop folder. When I check the file again on the desktop, they have lost over 3/4 mbs! 

 

That's kind of annoying after shelling out on a decent DSLR and a decent Mac!

 

If I do as you say and export unmodified original, will I be literally exporting an unmodified original even if the image has been cropped previously?

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  • Staff

Hi Graham,

Welcome to Affinity Forums :)

Are you sure you are checking the file size of JPG's on Apple Photos? In the second section of the Get info dialog you should have an icon of the format in front of the resolution/ MB size info. Does it says JPG or RAW?

 

Seems you are seeing the file size of the RAW images in Apple Photos and then when dragged to a folder they are considerably smaller because they were exported as JPG's which require a lot less space since they are compressed (at quality cost). If you want to keep the maximum quality possible, you have to export them as RAW's from Apple Photos to a folder going to menu File ▸ Export ▸ Export Unmodified Original.... Then open the RAW file in Affinity Photo and convert/develop them. RAW files are the RAW data captured by the camera sensor. They are not processed images like JPG's for example which were already converted/processed by the camera using a set of specific parameters defined by the manufacturer. If you open the RAW you are working with the original data without any edits/changes.

 

For general info about RAW's and related subjects take a look at the tutorials section of this site: Cambridge in Colour

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Dragging a jpeg out of Apple Photos creates a new jpeg that uses some intermediate jpeg compression level, typically one that compresses the image more than you get if you use the File > Export > "Export Photo ..." option & choose either the "High" or "Maximum" JPEG Quality setting. (The export dialog box also gives you several different image size options.)

 

This is probably why you are seeing reduced file sizes (& quality) if you drag & drop a photo out of Photos. Use the Export option instead to avoid this.

 

The Export Unmodified Original option does exactly that -- none of the edits you have done will be preserved. You will get a new jpeg exactly like the one that was added to the app.

All 3 1.10.8, & all 3 V2.4.1 Mac apps; 2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.8; Affinity Designer 1.108; & all 3 V2 apps for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Thanks for the replies.

MEB, the images in question are definitely JPEG, not RAW. I had been shooting in JPEG and RAW but I could never find the RAW file in Photos* - only the JPEG so I couldn't see the point in taking up hard drive space with RAW files I couldn't find! 

I am trying what MEB and RCR advise and using FILE > EXPORT > EXPORT UNMODIFIED ORIGINAL to ensure I do not loose any quality.

There must be millions of Apple users out there who are emailing pictures and losing quality without realising.

 

 

*Bring back the good old days of the trusty user manuals!

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For jpegs in the Apple Photos library, you can use the other export option ("Export x Photos ...") if you want to send the edited version of the file to someone or use it in another app. That opens a dialog box with a number of options for the pixel dimensions of the export, the compression ("Quality") level, & what if any metadata you want the exported file to include. Since jpegs use lossy compression, there is always some optimization going on when you export a jpeg as anything besides the unmodified original, but by choosing the 'maximum' quality setting there will be no additional quality lost in the export, even if the file size changes.

 

JPEG+RAW photos imported into Apple Photos are "stacked," so they appear as a single photo even though both versions are imported. To use RAW images, including how to export them, see user Alley_Cat's "Helpful" answer in this Apple Support Communities topic.

All 3 1.10.8, & all 3 V2.4.1 Mac apps; 2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.10.8; Affinity Designer 1.108; & all 3 V2 apps for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 15.7

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Hi Graham,

Apple Photos stacks the thumbnails when there's RAW+JPEG versions available (see screenshot - thumbnails_stack). Note the small J and R on the top right of the thumbnail. To switch between them enter in Edit Photo mode ( the interface becomes black), right-click on the image and select Use Raw as Original or Use JPEG as Original depending on the case (see screenshot - choose_format).

 

post-59-0-79197500-1471867409_thumb.png

 

post-59-0-95719500-1471867393_thumb.png

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