I have tried to follow the various threads about giving a dmg a custom icon, and it all seemed to work - indeed I saw a display of the customised dmg file during the creation process. But when I look at the resultant dmg file on the Mac Finder, or in the ‘Get Info’ for the dmg, I just see the same old generic icon. What did I do wrong?
(Using DropDMG 3.5.3 on a MacBook Pro with Mac OS High Sierra 10.13.4)
It sounds like you just misunderstood what it’s supposed to do. The custom icon is for the mounted disk image volume, not for the .dmg file. It doesn’t make sense to have a custom icon for the .dmg file because, due to the way macOS stores custom icons, it would be stripped away when you uploaded the .dmg file or transferred it to another Mac.
OK, I must have misunderstood. But if the dmg icon is the only thing a user sees at the start of the installation process, it seems to me it should resemble the icon for the app itself, perhaps with “installer” imposed on it, which is what I designed. Ah well. However, that then begs the question as to what the custom icon is for. I had already set up an icon for the program itself, and this worked before I used the ‘custom icon’ feature. Sorry to be dumb, but I would be grateful for a longer explanation.
Your point about the icon being stripped away may be related to some problems I’ve had uploading a dmg file to a web site and then downloading it. On double-clicking the downloaded dmg, I have had a strange error “legacy image should be converted”, which I suppose comes from the OS disk mounter app. However, I only had this when I used a particular FTP client, Transmit. When I used FileZilla it was OK. Normally Transmit is perfectly reliable. I am way over my head on this one.
For example, in the Finder choose Go > Computer. That will show your list of volumes. Depending on the Finder preferences, they may also show up on the Desktop. When you double-click the .dmg file, your custom icon will show up in these places, as well as in the title bar of the window.
I don’t think there’s any relation between that error and uploading the .dmg file. A legacy image is one created with an old version of macOS. The format is slightly different but still compatible with newer versions. You can remove the warning, as it says, by using DropDMG to convert the .dmg file (even to the same format). This will bring it up to date.
Michael, thanks for staying with me - it must be tedious to answer these dumb questions. Well, I think I did what you said, but I didn’t see anything. Obviously I can re-do the dmg to try to make sure the icon is there. When you suggest Go > Computer, all I get is a list of the usual suspects (Applications, Dropbox etc) with their own little monochrome icons. If I have already double-clicked on the dmg file, I get it represented by a standard monochrome representation of a disc - I tend to think of icons as coloured, but maybe that is stupid in this context. The icon of the dmg itself (in this example, I put it on the desktop) is unaffected. Maybe I just didn’t manage to attach the icon. I will try once more. It has to be said that DropDMG itself doesn’t give any visual feedback that the attachment has or hasn’t taken place.
As to the other issue, I’m not sure where the conversion of the file is allowed or catered for in DropDMG: of course it must be there, but I did not see it in the Configurations or Advance. Of course, I didn’t really create the installer with an earlier version of MacOS, as everything I’ve been doing has been done in the last few days on the same computer - so the problem really does appear to be an issue with the Transmit FTP client. I realise this is a different issue and that it should have been dealt with under another subject line.
You seem to be referring to the monochrome icons in the sidebar of the Finder window. I’m talking about the main part of the Finder window. When you choose Go > Computer, you should see your hard drive, perhaps a Time Machine volume, Network, Remote Disc, and any mounted disk images.
Right, as I said above, it’s the mounted disk image, i.e. the virtual disk that you see when you double-click the .dmg file, that gets the custom icon. Please see here for an example. Without the custom icon, it would be pure white instead of having the DropDMG icon badged on it.
The Preferences window is for configuring DropDMG’s settings. Actions are performed in the main window or from the File menu. You may also want to look at the Basics section of the manual, as I think it will make more sense if you see the big picture.
I really think there must be some other factor here. A regular .dmg file will survive transfer via Transmit just fine. It will have exactly the same size, contents, and checksum as the original.