No this is not what im talking about.
You can convert an image from one format to another in hundreds of ways, converters.
I mean the situation when the texture was added to the project in Sketchup has the TGA format and, for example, has an alpha channel, if I click on the button to open the texture in a third-party editor (the button that is on the materials board, the editor in which this texture will open is setting up in the preferences in the sketchup ). So it opens in Photoshop in JPG format, i.e. the sketchup cannot export TGA without conversion, it is a pity that it does not convert at least to PNG, the loss of image quality and alpha channel is very inconvenient.
Therefore, the only way is to change all textures in the project extension to PNG. Cause after it they opens as PNG and there are no losses, you edit the texture, save it, then add it back to the project.