Resizing image file without losing quality

[footballfan993]

I want to know if there is a way to lower the image file size without losing the quality of the photos. I have a Mac, the built in Photos app, Photoshop, and Lightroom. I'll include some pictures that I want to resize.

Thank You

 

[Ysarex]

In Photoshop from the Image menu select Image Size. Change the pixel dimensions to your new size. Note the dropbox and select the interpolation method you'd prefer to use. Adobe recommends Bicubic sharp for reduction. I would prefer Bilinear with sharpening done by hand afterward.

Joe

 

[dennybeall]

An adjunct to that process is to do it in smaller steps if you are going to make a big change either up or down.

 

[KmH]

Note that image size (resizing) and reducing image file size are 2 distinctly different things.

Why do you want to change the images size or file size? For electronic display? For print?

For electronic display you will see no difference in quality if you reduce the file size.
Most web sites have a limit on how big an image file can be.

Most web sites automatically resize your photos according to specification the web site sets.

 

[footballfan993]

My apologies, what I want to decrease is the file size, so the GB size, of the photo, I don't want to crop or change the size of the image itself. I want to change the storage size of the file. And for those wondering, it would be for Electronic display on my website that I am building. the file size has to be less than 100MB, I believe that is the correct size, I'm currently at work, but I can get the correct file size when I get home.

Thank You!

 

[KmH]

For electronic display you will see no difference in quality if you reduce the file size.

On TPF the file size limit to post, not hosted on some other web site, is something like 2.2 MB.

So 100 MB is a huge file size allowance.

 

[footballfan993]

For electronic display you will see no difference in quality if you reduce the file size.

On TPF the file size limit to post, not hosted on some other web site, is something like 2.2 MB.

So 100 MB is a huge file size allowance.

Thanks, again, I'll have to check the specific size limit allowed, the reason for this limit is that it's for a website that I'm building for a class that I'm taking, and I have to follow specific file size limits. But how do i reduce the file size of an image?

 

[footballfan993]

I got the correct file size limit, it is 100KB. Most of the photos are greater that 1MB, so I need to convert the file size down to less than 100KB.

 

[Solarflare]

Whow, 100KB is indeed a steep limit to image file size.

What you want is not possible without loss of resolution and image quality. Otherwise nobody would use these large files, would they now.

However since you're in a course and get forced down to this filesize, obviously the professor has no reason to complain if you do so.

I would try to use 6 Megapixel (3000x2000) or even 3 Megapixel (something like 2100x1400) and then use a high JPEG compression to reach 100KB.

 

[407370]

If the pics are part of the design then think about what resolution most monitors run at. I use 1680 x 1050 so any graphic longer than 1680 pixels causes display issues like scrolling or causes extra coding to auto size. Graphics sized for web are better looking that heavily compressed larger pictures
original:

Compressed below 100Kb

Sized and compressed:

Rather than just use compression think about the context the graphics will be used.

If the exercise is just to compress graphics then destroy the pics and pass the course but in real web design the context would determine what graphics were used.

 

[KmH]

For most photos you're going to have trouble getting down to 100 kb.

You'll need to use the For The Web option and strip all the image metadata, and even then you may have to crop some images to decrease the image resolution (pixel dimensions).

 

[footballfan993]

ok, thank you all for your help.

 

[dennybeall]

Was thinking an example may be interesting so I took a quick and dirty panorama that is 6464X2708 ppi (over 5 mb) and reduced it to 700X293 ppi with PS. Here's the result:

For display on the internet it's fine at 72ppi. You can see all the way to the back of the pasture and the file size is 95.3 kb.

 

[astroNikon]

hope you had a fun time on Mackinac Island

 

[KmH]

Was thinking an example may be interesting so I took a quick and dirty panorama that is 6464X2708 ppi (over 5 mb) and reduced it to 700X293 ppi with PS. Here's the result:
View attachment 114119

For display on the internet it's fine at 72ppi. You can see all the way to the back of the pasture and the file size is 95.3 kb.

On the Internet and other electronic display, ppi is meaningless.
1 ppi or 100,000 ppi- the photo will be the same size regardless.