IrfanView - thumbnail sizes?

[Terry Pinnell]

I'm getting a bit confused about thumbnail sizes in IrfanView. Why do
sizes differ please, for a given setting? For example, in the folder
partly shown in this screenshot
http://www.terrypin.dial.pipex.com/Images/IrfanViewThumbs2.gif
I have two identical images, but they are different sizes: 299x397
(top right of screenshot), and 656x875 (bottom left).
Their proportions are virtually identical, so why don't both
completely fill the 150x150 thumbnail area? (I've deliberately set it
to a distinct colour for this screenshot; I'd normally use the same as
the background.)

I'm aware of the option in Thumbnail Options 'Stretch small images to
thumbnail size', but surely that should only apply to images below the
set thumbnail size, which here is 150x150, well below the size of my
smaller image.

 

[Guest]

perhaps one of the images has an embeded thumnail and irfanview is using
that?
Seems like a slim chance since your photos look like they are from the same
camera... but I may be wrong.

 

[Terry Pinnell]

perhaps one of the images has an embeded thumnail and irfanview is using
that?
Seems like a slim chance since your photos look like they are from the same
camera... but I may be wrong.

Thanks, but no 'embedded thumbnail' as far as I know. (What exactly
*is* one of those anyway? Sounds painful!)

Is there perhaps a need to 'rescan' thumbnails in IV, as I've found
there is sometimes in ThumbsPlus after external changes to the file
name etc? If so, apart from the standard F5 Refresh command, I haven't
found the IV tool for this.

 

[Guest]

Some jpg images have the thumbnail images inside the main image thus
"embeded".
If you used a program to edit that picture (like photoshop) or the camera
supports it, perhaps it DOES have an embeded thumbnail. That would explain
the difference in the thumbnail size. I have seen this before.

Now dispay programs (like irfanview and acdsee) sometimes use this embeded
thumbnail to display the thumbnail instead of creating a new one on the fly.

 

[David Gilbert]

I'm getting a bit confused about thumbnail sizes in IrfanView. Why do
sizes differ please, for a given setting? For example, in the folder
partly shown in this screenshot
http://www.terrypin.dial.pipex.com/Images/IrfanViewThumbs2.gif
I have two identical images, but they are different sizes: 299x397
(top right of screenshot), and 656x875 (bottom left).
Their proportions are virtually identical, so why don't both
completely fill the 150x150 thumbnail area? (I've deliberately set it
to a distinct colour for this screenshot; I'd normally use the same as
the background.)

I'm aware of the option in Thumbnail Options 'Stretch small images to
thumbnail size', but surely that should only apply to images below the
set thumbnail size, which here is 150x150, well below the size of my
smaller image.

It appears to be a bug in IrfanView: I made two images the same size
as yours, at 80x80 they appear the same size as thumbs, 100x100 OK,
150x150 different as yours, 200x200 OK, 300x300 different again.
Ticking 'Stretch....) and starting from 80x80, 150x150 came out the
same size but this was not consistent.

 

[Terry Pinnell]

It appears to be a bug in IrfanView: I made two images the same size
as yours, at 80x80 they appear the same size as thumbs, 100x100 OK,
150x150 different as yours, 200x200 OK, 300x300 different again.
Ticking 'Stretch....) and starting from 80x80, 150x150 came out the
same size but this was not consistent.

Thanks for taking the trouble, David. Pleased to know it's not down to
user error for once. I'll email Irfan.