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Something wrong that isn't right. - Printable Version

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Something wrong that isn't right. - Krikor - 09-21-2024

Hello everyone!

Why doesn't the image I downloaded from pngwing.com appear when I open it in GIMP?  Huh

I can see the preview of the image in the Windows file manager;
[attachment=12364]

I can open it without problems in Paint and Inkscape but in GIMP it only shows a semi-transparent image. (See image below).
[attachment=12365]

I'm not worried about using this image exclusively, since I'm just experimenting to achieve a certain effect.
In fact, I used the image opened in Inkscape and saved it as .png and that way it opened without problems in GIMP.  Cool

The question here is why the image is not being displayed correctly with GIMP!?  Dodgy

Thanks in advance.

The image is License - Non-commercial use, so I left it attached for anyone who wants to check it.


RE: Something wrong that isn't right. - MrsP-from-C - 09-21-2024

Opens fine with my GIMP


RE: Something wrong that isn't right. - Ofnuts - 09-21-2024

Image opens fine for me in Gimp (2.10.34).

When I open your image, it is an indexed PNG. The spider is black and black is often the default color to mark transparent things. Further more the colormap contains many instances of #000000, which seem to correspond to anti-aliasing pixels on the edges. These pixels are partially opaque so may be the color indexing is really to RGBA values.

Edit: so yes, in a PNG the color map entries can have an associated alpha, so it makes sense to have several #000000 entries, each with its own alpha value.


RE: Something wrong that isn't right. - rich2005 - 09-21-2024

Much the same as Ofnuts.  I am not able to make it vanish either stand-alone or imported into a new image.

This the colormap Top is original Bottom is indexed -> RGB -> back to indexed.

[attachment=12369]


RE: Something wrong that isn't right. - PixLab - 09-21-2024

Like every one, your image opens just fine in my GIMP


RE: Something wrong that isn't right. - Krikor - 09-22-2024

Apparently only my GIMP is capable of doing this kind of magic (trying to be optimistic here).

I didn't understand if any explanation was given as to why this is happening. It seems like it's something I'll have to accept.

What I found strangest was the fact that other video editors, even the Windows file manager, had no problem with this image.

Just to confirm my story, I'm leaving two mini videos showing this occurrence.

https://imgur.com/PMPp0Fg - Invisible Spider in GIMP I

https://imgur.com/bI0PeGS  - Visible Spider In Inkscape II

Thank you all for your collaboration!


RE: Something wrong that isn't right. - PixLab - 09-22-2024

To try to find the root's problem, I went to the website you've mentioned and searched for spider.
I did find 3 different png of the "same" image, all of them with different size and quality, all of them smaller than the one you did put in your first post.

https://www.pngwing.com/en/free-png-yhctq > has badly cut surrounding white > Not indexed
https://www.pngwing.com/en/free-png-mafkv > seems to be the best version but is very little (512 px), and gray > The only one indexed with a strange palette https://imgur.com/6REBVbx and https://imgur.com/VTC9eu1
https://www.pngwing.com/en/free-png-zhlgs > no anti-aliasing, has ugly "stairs" all around > Not indexed

I did stop there to search as I go thru so many pages already, but none of them match 100% yours.

Some solutions to investigate?
Maybe try with the one you uploaded on G-F? direct link > https://www.gimp-forum.net/attachment.php?aid=12366 , why try with it? because it's on a Linux server and it would be interpreted by Firefox, should it makes a difference? No... but we never know, in all case that's the one we all tried with positive opening in GIMP Big Grin
If you could recall the page and give us the link it would be nice for us to test with the original, or maybe it was just a temporary download problem on your side?


RE: Something wrong that isn't right. - sallyanne - 09-22-2024

Opens fine in my 2.10.36.
Yes the mode is indexed. I checked the channels too and they are indexed and alpha. Turn the eye off the alpha channel and you get a black square. Turn the indexed channel off and the black spider remains.
*Threshold Alpha (under layer - transparency) at value one turns the spider invisible.


RE: Something wrong that isn't right. - Krikor - 09-22-2024

(09-22-2024, 02:24 AM)PixLab Wrote: To try to find the root's problem, I went to the website you've mentioned and searched for spider.
I did find 3 different png of the "same" image, all of them with different size and quality, all of them smaller than the one you did put in your first post.

https://www.pngwing.com/en/free-png-yhctq > has badly cut surrounding white > Not indexed
https://www.pngwing.com/en/free-png-mafkv > seems to be the best version but is very little (512 px), and gray > The only one indexed with a strange palette https://imgur.com/6REBVbx and https://imgur.com/VTC9eu1
https://www.pngwing.com/en/free-png-zhlgs > no anti-aliasing, has ugly "stairs" all around > Not indexed

I did stop there to search as I go thru so many pages already, but none of them match 100% yours.

Some solutions to investigate?
Maybe try with the one you uploaded on G-F? direct link > https://www.gimp-forum.net/attachment.php?aid=12366 , why try with it? because it's on a Linux server and it would be interpreted by Firefox, should it makes a difference? No... but we never know, in all case that's the one we all tried with positive opening in GIMP  Big Grin
If you could recall the page and give us the link it would be nice for us to test with the original, or maybe it was just a temporary download problem on your side?


PixLab,

I checked my browsing history and found the link:
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.pngwing.com%2Fen%2Ffree-png-ymfgq&psig=AOvVaw3pVj6j_K-UlkM9tlg0YMyB&ust=1727070346400000&source=images&cd=vfe&opi=89978449&ved=0CBQQjRxqFwoTCLDCzcbs1YgDFQAAAAAdAAAAABAE

Ok, I will try with the link you posted regarding the file I uploaded. If there is any change then I will comment here in the forum.

(09-22-2024, 04:24 AM)sallyanne Wrote: Opens fine in my 2.10.36.
Yes the mode is indexed. I checked the channels too and they are indexed and alpha. Turn the eye off the alpha channel and you get a black square. Turn the indexed channel off and the black spider remains.
*Threshold Alpha (under layer - transparency) at value one turns the spider invisible.

Hi Sally,

The difference here is that nothing changes if I turn off the indexed channel.

With Threshold Alpha, as you mentioned, nothing changes here, regardless of the adjustment I make to the values. From zero to one the image remains unchanged.

Thank you for helping with the investigation.


RE: Something wrong that isn't right. - denzjos - 09-22-2024

Windows 10, Gimp 2.10.38 : the spider loaded in gimp without any problem. (even my wife was shocked Big Grin )