Best Way Of Compressing An Image? Need Some Advice...

[Kjennings92]

Man, it really feels like I'm getting my toes into the editing side of things even though I don't actually do it on a daily basis.

 

Anyway, I'm needing to compress a few images so that I can upload them to the Vivaldi forum for a post I'm working on. (When I tried uploading 1 of the images I compressed earlier, it just said "Error" when I did so; it didn't even say WHY it couldn't be uploaded!  The only problem is I don't know the best way/method of compressing an image. I know there are some sites out there that exist, but honestly speaking, I have no idea about just how good they are if that. And I do know you can easily do so in certain applications as well. But the point is, I don't want my images to be reduced in terms of the resolution; just how big they are in size. (Eg, KB, MB, etc.)  It will be done on Windows since I don't really use any other os.

 

I sure hope someone here can educate me on how to do this properly so that I have the proper knowledge for the future. If you need any additional details or have questions, be sure to ask & I'll reply! :)

Thanks in advance!  

 

 

[tkitch]

What do you care about more, resolution or fidelity?

The only way to shrink in size is to lower the resolution, or lower the image quality.

 

What format are the images in now?

 

[Chris Pratt]

What image formats are you working with? There's lossy formats like JPEG and then lossless formats like PNG. You have two options to reduce the file size of image, which is really just the same option: you can reduce the actual size, which reduces the number of pixels to encode, or you can throw out information like colors or fine detail, which is again reducing the amount of unique pixels to encode.

 

Lossless formats focus mostly on efficiency to achieve "compression" and the only real option other than that is reduce the colorspace or the actual physical dimensions. With lossy formats, you have the additional option of removing detail, but that can be problematic for obvious reasons. Photos tend to hold up pretty well, since the human eye does a lot to fill in the visual gaps. Things like diagrams, charts, etc. don't do well at all, on the other hand, since fine detail is actually important. That's why JPEG remains a popular choice for photos, even though newer formats like PNG are better in almost every way. They just can't match the low file sizes JPEG can achieve by literally throwing out data.

 

Long and short, it depends on the type of image and what you need to convey. If it's photos, you should use JPEG and you can usually save them out at as low as 40% quality and still get a decent enough image for viewing on a device screen. If you have technical images or even photos where you need to maintain fine detail (you can't afford to lose anything), then you're stuck with a lossless format that is essentially incompressible. In that case, you have to take the hit to physical resolution if you need them to be smaller.

[Kjennings92]

30 minutes ago, tkitch said:

What do you care about more, resolution or fidelity?

The only way to shrink in size is to lower the resolution, or lower the image quality.

 

What format are the images in now?

 

Currently, they're in PNG. I'd prefer them to be of decent quality. Doesn't have to be amazing, but the ability to make out details & have a clear image is important. Also, forgot to mention in the post I had to use Greenshot instead of Snipping Tool simply because the delay function in S.T. wasn't working for what I had in mind when I took the screenshots. If I need to redo them, I guess I could. But I would prefer to explorer other options first.

Edited December 13, 2021 by Kjennings92

[tkitch]

Try converting to JPG and see what you think, they should be quite a bit smaller.

 

[Kjennings92]

10 minutes ago, tkitch said:

Try converting to JPG and see what you think, they should be quite a bit smaller.

 

That's an option I could try. Not sure if using 1 of those online compressors/converters earlier explained why I had an error while trying to upload the image, but I think this should be the better method anyway.

Edited December 13, 2021 by Kjennings92

[jones177]

Most file formats don't do compression. JPEG does. To use JPEG properly you need to use a program that gives you a choice of how much compression to use. 

 

In Photoshop when you select JPEG it gives you a choice between 1 and 12. 12 being no compression. For posting online with no visible artifacts 10 is used.

 

Some budget paint programs have these sliders too. Here is what it looks like in Affinity($24). 

As you move the slider the program gives you an estimate of the size.

 

Word of Warning.

Never use JPEG on original art work since it is a compression file format. 

I used PDF, TIFF and TGA.

 

[Nayr438]

You can try converting it to WebP if the platform your trying to upload supports it. WebP exported at 100% Quality, at least during my usage in Krita, usually results in a 25%-50% reduction in file size compared to png.

[Kjennings92]

2 hours ago, jones177 said:

Most file formats don't do compression. JPEG does. To use JPEG properly you need to use a program that gives you a choice of how much compression to use. 

 

In Photoshop when you select JPEG it gives you a choice between 1 and 12. 12 being no compression. For posting online with no visible artifacts 10 is used.

 

Some budget paint programs have these sliders too. Here is what it looks like in Affinity($24). 

As you move the slider the program gives you an estimate of the size.

 

Word of Warning.

Never use JPEG on original art work since it is a compression file format. 

I used PDF, TIFF and TGA.

 

I see. Normally, I don't use paid software just cause I can't afford them. Do I have any free options as far as compression goes?

[jones177]

9 hours ago, Kjennings92 said:

I see. Normally, I don't use paid software just cause I can't afford them. Do I have any free options as far as compression goes?

Gimp has the feature and is free.

https://www.gimp.org/

It is under export.