diff --git a/lib/app_ipc.cpp b/lib/app_ipc.cpp
index 3e77338edc..6e5b46f36a 100644
--- a/lib/app_ipc.cpp
+++ b/lib/app_ipc.cpp
@@ -27,7 +27,6 @@
 #include "filesys.h"
 #include "miofile.h"
 #include "parse.h"
-#include "str_replace.h"
 #include "str_util.h"
 #include "url.h"
 #include "util.h"
diff --git a/lib/str_util.h b/lib/str_util.h
index 008e1862ac..4777230d73 100644
--- a/lib/str_util.h
+++ b/lib/str_util.h
@@ -22,6 +22,8 @@
 #include <vector>
 #include <string.h>
 
+#include "str_replace.h"
+
 #define safe_strcpy(x, y) strlcpy(x, y, sizeof(x))
 #define safe_strcat(x, y) strlcat(x, y, sizeof(x))
 
diff --git a/lib/url.cpp b/lib/url.cpp
index cb7c76b255..6ab7045215 100644
--- a/lib/url.cpp
+++ b/lib/url.cpp
@@ -174,8 +174,10 @@ void escape_url(string& url) {
     url = buf;
 }
 
-// Escape a URL for the project directory, cutting off the "http://",
+// Escape a project URL, cutting off the "http://",
 // converting everthing other than alphanumbers, ., - and _ to "_".
+// This is used as the project directory name.
+// Note: does not convert to lowercase.
 //
 void escape_url_readable(char *in, char* out) {
     int x, y;
diff --git a/lib/util.cpp b/lib/util.cpp
index 55413de728..b3207604eb 100644
--- a/lib/util.cpp
+++ b/lib/util.cpp
@@ -17,7 +17,6 @@
 
 #if defined(_WIN32)
 #include "boinc_win.h"
-#include "str_replace.h"
 #include "str_util.h"
 #include "win_util.h"
 #endif
@@ -798,16 +797,32 @@ int DOCKER_CONN::parse_container_name(string line, string &name) {
 string docker_image_name(
     const char* proj_url_esc, const char* wu_name
 ) {
-    char buf[1024];
-    sprintf(buf, "boinc__%s__%s", proj_url_esc, wu_name);
+    char buf[1024], url_buf[1024], wu_buf[1024];;
+
+    // Docker image names can't have upper case chars
+    //
+    safe_strcpy(url_buf, proj_url_esc);
+    downcase_string(url_buf);
+    safe_strcpy(wu_buf, wu_name);
+    downcase_string(wu_buf);
+
+    sprintf(buf, "boinc__%s__%s", url_buf, wu_buf);
     return string(buf);
 }
 
 string docker_container_name(
     const char* proj_url_esc, const char* result_name
 ){
-    char buf[1024];
-    sprintf(buf, "boinc__%s__%s", proj_url_esc, result_name);
+    char buf[1024], url_buf[1024], result_buf[1024];;
+
+    // Docker image names can't have upper case chars
+    //
+    safe_strcpy(url_buf, proj_url_esc);
+    downcase_string(url_buf);
+    safe_strcpy(result_buf, result_name);
+    downcase_string(result_buf);
+
+    sprintf(buf, "boinc__%s__%s", url_buf, result_buf);
     return string(buf);
 }