Photo Editing & Graphic Design forum

General discussion

Batchconvert pictures in filesize?

by tobiaskarlsson / June 11, 2010 2:46 AM PDT

Hi, I've searched all cnet and spent ous on the web looking for a program that kan batch convert pictures to the same FILE size, for example 80k. I found a huge selection that batch convert all kinds of way, picture size etc...

I also tried Photoshops "Save for web and..." ut that reall didn't work so good in "batch modes"

Please, if anyone knows of such a program, please let me know!

I think it's strange that I vouldnt find one as that would be a useful "batch" for al lot o f people:-)

Best Regards

Tobias Karlsson in Sweden

Post a reply
Discussion is locked
You are posting a reply to: Batchconvert pictures in filesize?
The posting of advertisements, profanity, or personal attacks is prohibited. Please refer to our CNET Forums policies for details. All submitted content is subject to our Terms of Use.
Track this discussion and email me when there are updates

If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.

You are reporting the following post: Batchconvert pictures in filesize?
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
Collapse -
We looked for that.
by R. Proffitt Forum moderator / June 11, 2010 3:03 AM PDT

In fact there is no such thing. Here's why. JPEG COMPRESSION is variable. A picture of say a white or single color sheet will compress handily down to a low number of bytes. An image with a flock of seagulls flying pass a rainbow billboard will not compress as well.

Hope the short version is enough for you but there are great tutorials and programmer's reference about image compression. Once you learn all that, you will then see why you can't ask for this.

Collapse -
OK, I know what you mean:-)
by tobiaskarlsson / June 11, 2010 3:37 AM PDT
In reply to: We looked for that.

Thanks for you FAST answer!

>Here's why. JPEG COMPRESSION is variable

Yes, I undrestand that:-)
But I thought there was som kind of program that could calculate and convert by file size output.

Adobe Photshop is close with it's "save for web something...", there you can clickon the upper left and choose "optimize for file size", but it doesn't work so good when creating an "action" command and the using a batch...

Best Regards

Tobias Karlsson in Sweden

Collapse -
Ok, you could ask for that.
by R. Proffitt Forum moderator / June 12, 2010 11:18 PM PDT

And the calculations required would mean this app would calculating for days as it tried each possible LOSSY COMPRESSION SETTING.

To really understand this you would have to start reading a lot more about JPEG compression. I know that at first you would ask this question and think "why not" but after you got enough learning you would then think "I see why not."

Collapse -
Hmmm, I don't agree
by tobiaskarlsson / June 13, 2010 5:57 AM PDT

I don't want to debate if you are right or wrong;

Please take a look in Adoe Photoshop and you will see that these kind of calculations already exists, doesn't take long time do do, and is rather accurate!

Two different ways in Adobe;

One example is when you choose "Save As" and when you select the jpg option you can push a "slider" to get the desired file size, this does not take long, millisecond in my computer, and mine is not the fastest one:-)

Or you can, as I mentioned, using the "Save for Web & Devices" and then click in the right upper corner. You can then "Optimize for file size", choose how big you want the file size, click ok and save and it's done, the calculation takes no time either but it's boring doing this to a large amount of pictures.

So I know the function already exists, BUT, I'm looking for a program that can do it automatically in a batch, maybe some one written a "macro" to Adobe, anyone?

PLEASE be sure of that I'm NOT trying to be a wise guy or try to just be rude, but I cant understand why you're saying that this calculating would be so hard for the computer making it almost impossible in the real world when as I see it already exists and can be done, I just want a way to make it in a batch:-)
Oh, and ofcourse, when using these above two ways in Adobe to decide the output file size, it of course has to be reasonable changes, you cant go from 44M to 44kb, you CAN change the file size VERY much!

Thank you so much for taking you time!

Best Regards

Tobias Karlsson in Sweden

Collapse -
Then you have a solution?
by R. Proffitt Forum moderator / June 13, 2010 6:40 AM PDT
In reply to: Hmmm, I don't agree

I'm just an author of some apps, electronics designer, embedded apps and more. One of the systems I worked on was a taxi camera where we had this need to get the pictures to exactly some bytes. This is my background and why I wanted to discuss this.

If we didn't use JPEG compression it may be more predictable.

Sorry that I offended you in any way and hope you see fit to ask Adobe to supply a script for you.

Collapse -
No no no no, you have not offened me:-)
by tobiaskarlsson / June 13, 2010 7:14 AM PDT

PLEASE understand that you have not offended me in any way and I appreciate that you're taking the time!!!
Maybe its one of those language barriers:-)

I'm just curious, have you checked out these options I mentioned in my previous?

I'm using these daily when I want for an example a 80k jpg pic from 2M, they may vary a kilo or two, but it's close enough for me, I just want to "automate" it!

Interesting that you already been thinking of this in your job! I can see the use for it in "watchout cameras" in taxicars.

Check out what I mentioned earlier, it works well with jpg's and Adobe PS do it fast!

Thank you so much, it's just a healthy discussion:-)

Best Regards

Tobias Karlsson in Sweden

Collapse -
I use
by R. Proffitt Forum moderator / June 13, 2010 12:05 PM PDT

IRFANVIEW to do batch conversions but your "specification" is one I'm personally familiar with since it came up in the product design. The really sad part about it was the lost time over that spec. If they had left it a little loose say from 10 to 12 Kilobytes rather than 10,000 exact bytes we would have saved months going over why JPEG doesn't do that. We could have cheated and over compressed and then filled some bytes with extraneous data but why do that?

And yes I checked such options in the past. But let's say it's true. Why not talk to those that got this done?

In the meantime I'm unsure if you looked at IRFANVIEW.

Collapse -
by tobiaskarlsson / June 14, 2010 12:06 AM PDT
In reply to: I use


I downloaded Irfanview (used to have it!) and i do EXACTLY what I want batch converting with a file size rule, and you can also set the "longest side" to be a specific number, I used 800p.

It worked out VERY good, nice looking pics (the quality is what you could expect from a heavy compressed pic)

I use to have Irfanview, it's realy nice!

>But let's say it's true. Why not talk to those that got this done?

Not necessary now when I got Irfanview;-)

Maybe it was me not making it clear that it didn't have to make the pics EXACTLY (for example) 80k on the byte! 1 or 2 kg diff was ok. My apologizes!

Irfanview differed no more than 1k in my test I did, and always under the decided target size, very good:-)

So, in the end, you helped me!

Thanks and take care

Tobias Karlsson

Collapse -
Me and specifications.
by R. Proffitt Forum moderator / June 14, 2010 12:40 AM PDT
In reply to: Hey

I apologize for that. It's something I am programmed to do. If the "contract" calls for "it shall do this" then I have to make it do that.

In the end I see you wanted only something "close to" so many K which that has solutions but for very deep reasons the software to compress to an exact number of bytes isn't there due to how many passes we'd have to take to see what comes out.

Glad we got there,

Collapse -
by W N W / June 27, 2010 12:41 AM PDT

I know you have already solved this one with the absolutely fine application Ifanview (it truly is amazing and I use it myself, often!), but I wanted to put in a plug for one of my other favorite applications and that is the Faststone Photo Resizer. It will fulfill your needs and it also does a great deal more. You can find it at They have some other cools stuff, too. Oh, and it too is free of charge for non commercial use. I know this may be a little late, but I hope this information is helpful to you.

Collapse -
Solved - New!
by tobiaskarlsson / June 27, 2010 10:08 AM PDT
In reply to: Solved

Thanks for you interest in this:-)

But I failed to see how Faststone would make a solution to this, I've downloaded it (it's a really good program) but I didn't find that option to save pics to a specific file size.
Thanks anyway to contribute:-)

Tobias Karlsson in Sweden

Collapse -
by W N W / June 28, 2010 12:03 AM PDT
In reply to: Solved - New!

Hi there! I may not be understanding your requirements correctly, but if you look under advanced options and select the Resize tab, then check the Resize box (if you don't check it, you won't see the options), you will see options to resize by 'pixels', 'percentages' or 'resize based on one side'. Under the 'Pixels' option, you can specify exactly what size you want your output file(s) to be. However, that may not be what you need. I hope this helps!

Collapse -
by tobiaskarlsson / June 28, 2010 12:51 AM PDT
In reply to: Solved

>Under the 'Pixels' option, you can specify exactly what size you want your output file(s) to be.

Yes, I saw that, but what I was looking for is an option in a batch saves by choosing a specific file size (kb or M), not pic size:-)

But it's a nice program!

Thanks anyway

Tobias Karlsson

Popular Forums
Computer Help 51,224 discussions
Computer Newbies 10,453 discussions
Laptops 20,090 discussions
Security 30,722 discussions
TVs & Home Theaters 20,937 discussions
Windows 10 1,295 discussions
Phones 16,252 discussions
Windows 7 7,684 discussions
Networking & Wireless 15,215 discussions


Roku Streaming Stick 2016

Roku has the most apps, the simplest interface and the best search, making it CNET's favorite way to stream Netflix, Amazon, Hulu, HBO and all the rest.